Immunoglobulin domain; The members here are composed of the immunoglobulin (Ig) domain found in the Ig superfamily. The Ig superfamily is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. Members of this group are components of immunoglobulin, neuroglia, cell surface glycoproteins, including T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins, including butyrophilin and chondroitin sulfate proteoglycan core protein. A predominant feature of most Ig domains is a disulfide bridge connecting the two beta-sheets with a tryptophan residue packed against the disulfide bond. Ig superfamily (IgSF) domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Typically, the V-set domains have A, B, E, and D strands in one sheet and A', G, F, C, C' and C" in the other. The structures in C1-set are smaller than those in the V-set; they have one beta sheet that is formed by strands A, B, E, and D and the other by strands G, F, C, and C'. Moreover, a C1-set Ig domain contains a short C' strand (three residues) and lacks A' and C" strand. Unlike other Ig domain sets, C2-set structures do not have a D strand. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325   46 LFVEKPQTGSVKVGANITFVAKVRAEDLLRKPTVKWFKGKWMDLASKAGKHLQLKETFERQTRVYTFEMQIIKAKENYAG 125
Cdd:cd20962     1 LFVMRPQDGEVTVGGSITFSARVAGASLLKPPVVKWFKGKWVDLSSKVGQHLQLHDSYDRASKVYLFELHITDAQPAFAG 80

                          90       100
                  ....*....|....*....|.
gi 568966325  126 NYRCEVTYKDKFDSCSFDLEV 146
Cdd:cd20962    81 GYRCEVSTKDKFDCSNFNLTV 101

Immunoglobulin I-set domain;

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325  1034 PMFTQPLVNTYAIAGYNATLNCSVRGNPKPKITWMKNKVAIVDDPRYRMFSNQGVCTLEIRKPSPYDGGTYCCKAVNDLG 1113
Cdd:pfam07679    1 PKFTQKPKDVEVQEGESARFTCTVTGTPDPEVSWFKDGQPLRSSDRFKVTYEGGTYTLTISNVQPDDSGKYTCVATNSAG 80

                           90
                   ....*....|
gi 568966325  1114 TVEIECKLEV 1123
Cdd:pfam07679   81 EAEASAELTV 90

Fibronectin type 3 domain; One of three types of internal repeats found in the plasma protein fibronectin. Its tenth fibronectin type III repeat contains an RGD cell recognition sequence in a flexible loop between 2 strands. Approximately 2% of all animal proteins contain the FN3 repeat; including extracellular and intracellular proteins, membrane spanning cytokine receptors, growth hormone receptors, tyrosine phosphatase receptors, and adhesion molecules. FN3-like domains are also found in bacterial glycosyl hydrolases.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325  607 PDPPVAPNVTEVGDDWCIMNWEPPAYDGGsPILGYFIERKKKQSSRWMRLNFDLCKETTFEPKKMIEGVAYEVRIFAVNA 686
Cdd:cd00063     1 PSPPTNLRVTDVTSTSVTLSWTPPEDDGG-PITGYVVEYREKGSGDWKEVEVTPGSETSYTLTGLKPGTEYEFRVRAVNG 79

                          90
                  ....*....|
gi 568966325  687 IGISKPSMPS 696
Cdd:cd00063    80 GGESPPSESV 89

Tri-helix bundle domain; This domain can be found in the myosin-binding motif (m-domain) region present in myosin-binding protein C (MyBP-C). MyBP-C is a sarcomeric assembly protein necessary for the regulation of sarcomere structure and function. The MyBP-C family of proteins consists mainly of modules with immunoglobulin (Ig) or fibronectin folds. This domain exhibits a three-helix bundle fold and there is a known actin-binding motif, LK(R/K)XK positioned in the third helix (alpha3), similar to that found in villin and related proteins.

                           10        20        30
                   ....*....|....*....|....*....|....
gi 568966325   196 DVWELLKNANPNEYEKIAFQYGITDLRGMLKRLK 229
Cdd:pfam18362    1 DVWEILSNAPPKDYEKIAFQYGITDLRGMLKKLK 34

Immunoglobulin domain; The members here are composed of the immunoglobulin (Ig) domain found in the Ig superfamily. The Ig superfamily is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. Members of this group are components of immunoglobulin, neuroglia, cell surface glycoproteins, including T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins, including butyrophilin and chondroitin sulfate proteoglycan core protein. A predominant feature of most Ig domains is a disulfide bridge connecting the two beta-sheets with a tryptophan residue packed against the disulfide bond. Ig superfamily (IgSF) domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Typically, the V-set domains have A, B, E, and D strands in one sheet and A', G, F, C, C' and C" in the other. The structures in C1-set are smaller than those in the V-set; they have one beta sheet that is formed by strands A, B, E, and D and the other by strands G, F, C, and C'. Moreover, a C1-set Ig domain contains a short C' strand (three residues) and lacks A' and C" strand. Unlike other Ig domain sets, C2-set structures do not have a D strand. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 568966325   421 KITTPLTDQTVKLGKEVCLKCEISENVPGK--WTKNGLPVQEGERLKVVHKGRIHKLVIANALIEDEGEYVFT 491
Cdd:pfam07679    2 KFTQKPKDVEVQEGESARFTCTVTGTPDPEvsWFKDGQPLRSSDRFKVTYEGGTYTLTISNVQPDDSGKYTCV 74

Immunoglobulin Domain C1 of human cardiac Myosin Binding Protein C and similar proteins; a member of the I-set of IgSF domains; The members here are composed of the immunoglobulin domain C1 of human cardiac Myosin Binding Protein C (MyBP-C). MyBP-C is a thick filament protein involved in the regulation of muscle contraction. Mutations in cardiac MyBP-C gene are the second most frequent cause of hypertrophic cardiomyopathy. MyBP-C binds to myosin with two binding sites, one at its C-terminus and another at its N-terminus. The N-terminal binding site, consisting of immunoglobulin (lg) domains C1 and C2 connected by a flexible linker, interacts with the S2 segment of myosin in a phosphorylation-regulated manner. The C1 and C2 Ig domains can bind to and activate or inhibit the thin filament. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. The C1 domain of the MyBP-C is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand but lack a C" strand. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325   46 LFVEKPQTGSVKVGANITFVAKVRAEDLLRKPTVKWFKGKWMDLASKAGKHLQLKETFERQTRVYTFEMQIIKAKENYAG 125
Cdd:cd20962     1 LFVMRPQDGEVTVGGSITFSARVAGASLLKPPVVKWFKGKWVDLSSKVGQHLQLHDSYDRASKVYLFELHITDAQPAFAG 80

                          90       100
                  ....*....|....*....|.
gi 568966325  126 NYRCEVTYKDKFDSCSFDLEV 146
Cdd:cd20962    81 GYRCEVSTKDKFDCSNFNLTV 101

Immunoglobulin I-set domain;

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325  1034 PMFTQPLVNTYAIAGYNATLNCSVRGNPKPKITWMKNKVAIVDDPRYRMFSNQGVCTLEIRKPSPYDGGTYCCKAVNDLG 1113
Cdd:pfam07679    1 PKFTQKPKDVEVQEGESARFTCTVTGTPDPEVSWFKDGQPLRSSDRFKVTYEGGTYTLTISNVQPDDSGKYTCVATNSAG 80

                           90
                   ....*....|
gi 568966325  1114 TVEIECKLEV 1123
Cdd:pfam07679   81 EAEASAELTV 90

Fibronectin type 3 domain; One of three types of internal repeats found in the plasma protein fibronectin. Its tenth fibronectin type III repeat contains an RGD cell recognition sequence in a flexible loop between 2 strands. Approximately 2% of all animal proteins contain the FN3 repeat; including extracellular and intracellular proteins, membrane spanning cytokine receptors, growth hormone receptors, tyrosine phosphatase receptors, and adhesion molecules. FN3-like domains are also found in bacterial glycosyl hydrolases.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325  607 PDPPVAPNVTEVGDDWCIMNWEPPAYDGGsPILGYFIERKKKQSSRWMRLNFDLCKETTFEPKKMIEGVAYEVRIFAVNA 686
Cdd:cd00063     1 PSPPTNLRVTDVTSTSVTLSWTPPEDDGG-PITGYVVEYREKGSGDWKEVEVTPGSETSYTLTGLKPGTEYEFRVRAVNG 79

                          90
                  ....*....|
gi 568966325  687 IGISKPSMPS 696
Cdd:cd00063    80 GGESPPSESV 89

Immunoglobulin domain; The members here are composed of the immunoglobulin (Ig) domain found in the Ig superfamily. The Ig superfamily is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. Members of this group are components of immunoglobulin, neuroglia, cell surface glycoproteins, including T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins, including butyrophilin and chondroitin sulfate proteoglycan core protein. A predominant feature of most Ig domains is a disulfide bridge connecting the two beta-sheets with a tryptophan residue packed against the disulfide bond. Ig superfamily (IgSF) domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Typically, the V-set domains have A, B, E, and D strands in one sheet and A', G, F, C, C' and C" in the other. The structures in C1-set are smaller than those in the V-set; they have one beta sheet that is formed by strands A, B, E, and D and the other by strands G, F, C, and C'. Moreover, a C1-set Ig domain contains a short C' strand (three residues) and lacks A' and C" strand. Unlike other Ig domain sets, C2-set structures do not have a D strand. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 568966325 1051 ATLNCSVRGNPKPKITWMKNKVAIVDDPRYRMFSNQGVCTLEIRKPSPYDGGTYCCKAVNDLGTVE 1116
Cdd:cd00096     1 VTLTCSASGNPPPTITWYKNGKPLPPSSRDSRRSELGNGTLTISNVTLEDSGTYTCVASNSAGGSA 66

Fibronectin type 3 domain; One of three types of internal repeat within the plasma protein, fibronectin. The tenth fibronectin type III repeat contains a RGD cell recognition sequence in a flexible loop between 2 strands. Type III modules are present in both extracellular and intracellular proteins.

                            10        20        30        40        50        60        70        80
                    ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325    919 PGPPQTVTIEDVWGENVALTWTPPKDDGNAA-ITGYTIQKaDKKSMEWFTVIEHYHRTNATITELVIGNEYYFRVFAENM 997
Cdd:smart00060    1 PSPPSNLRVTDVTSTSVTLSWEPPPDDGITGyIVGYRVEY-REEGSEWKEVNVTPSSTSYTLTGLKPGTEYEFRVRAVNG 79

                    ....
gi 568966325    998 CGLS 1001
Cdd:smart00060   80 AGEG 83

Tri-helix bundle domain; This domain can be found in the myosin-binding motif (m-domain) region present in myosin-binding protein C (MyBP-C). MyBP-C is a sarcomeric assembly protein necessary for the regulation of sarcomere structure and function. The MyBP-C family of proteins consists mainly of modules with immunoglobulin (Ig) or fibronectin folds. This domain exhibits a three-helix bundle fold and there is a known actin-binding motif, LK(R/K)XK positioned in the third helix (alpha3), similar to that found in villin and related proteins.

                           10        20        30
                   ....*....|....*....|....*....|....
gi 568966325   196 DVWELLKNANPNEYEKIAFQYGITDLRGMLKRLK 229
Cdd:pfam18362    1 DVWEILSNAPPKDYEKIAFQYGITDLRGMLKKLK 34

Fibronectin type 3 domain; One of three types of internal repeats found in the plasma protein fibronectin. Its tenth fibronectin type III repeat contains an RGD cell recognition sequence in a flexible loop between 2 strands. Approximately 2% of all animal proteins contain the FN3 repeat; including extracellular and intracellular proteins, membrane spanning cytokine receptors, growth hormone receptors, tyrosine phosphatase receptors, and adhesion molecules. FN3-like domains are also found in bacterial glycosyl hydrolases.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325  706 SPPTLLAVDSVTDSSVTMKWRPPDQIGAAgLDGYVLEYCfegstsakqsnengetacDLPAEDWIVANTDLIDKTKFTIN 785
Cdd:cd00063     2 SPPTNLRVTDVTSTSVTLSWTPPEDDGGP-ITGYVVEYR------------------EKGSGDWKEVEVTPGSETSYTLT 62

                          90       100
                  ....*....|....*....|...
gi 568966325  786 GLPTDAKIFVRVKAINAAGASEP 808
Cdd:cd00063    63 GLKPGTEYEFRVRAVNGGGESPP 85

Fibronectin type III domain;

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325   920 GPPQTVTIEDVWGENVALTWTPPkDDGNAAITGYTIQKADKKSME-WFTVIEHYHRTNATITELVIGNEYYFRVFAENMC 998
Cdd:pfam00041    1 SAPSNLTVTDVTSTSLTVSWTPP-PDGNGPITGYEVEYRPKNSGEpWNEITVPGTTTSVTLTGLKPGTEYEVRVQAVNGG 79

                   ....
gi 568966325   999 GLSE 1002
Cdd:pfam00041   80 GEGP 83

Immunoglobulin I-set domain;

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 568966325   421 KITTPLTDQTVKLGKEVCLKCEISENVPGK--WTKNGLPVQEGERLKVVHKGRIHKLVIANALIEDEGEYVFT 491
Cdd:pfam07679    2 KFTQKPKDVEVQEGESARFTCTVTGTPDPEvsWFKDGQPLRSSDRFKVTYEGGTYTLTISNVQPDDSGKYTCV 74

Immunoglobulin I-set domain;

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325   331 VTKQLEDMNAYCGERVEMEVEVSED-DANVKWFKNGEEIFPGpkSRYKIKVEGKKHTLIIEGATKADSAEYS--AMTTGG 407
Cdd:pfam07679    3 FTQKPKDVEVQEGESARFTCTVTGTpDPEVSWFKDGQPLRSS--DRFKVTYEGGTYTLTISNVQPDDSGKYTcvATNSAG 80

                   ....*...
gi 568966325   408 QSSAKLSV 415
Cdd:pfam07679   81 EAEASAEL 88

Immunoglobulin like; IG domains that cannot be classified into one of IGv1, IGc1, IGc2, IG.

                            10        20        30        40        50        60        70        80
                    ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325    428 DQTVKLGKEVCLKCEISENVP--GKWTKNGL-PVQEGERLKVVHKGRIHKLVIANALIEDEGEYVFTPDAYNVPLSAKVH 504
Cdd:smart00410    3 SVTVKEGESVTLSCEASGSPPpeVTWYKQGGkLLAESGRFSVSRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSGTT 82

                    ..
gi 568966325    505 VI 506
Cdd:smart00410   83 LT 84

Fibronectin type III domain;

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325   706 SPPTLLAVDSVTDSSVTMKWRPPDQIGAAgLDGYVLEYcfegstsaKQSNENgetacdlpaEDWIVANTDLiDKTKFTIN 785
Cdd:pfam00041    1 SAPSNLTVTDVTSTSLTVSWTPPPDGNGP-ITGYEVEY--------RPKNSG---------EPWNEITVPG-TTTSVTLT 61

                           90       100
                   ....*....|....*....|...
gi 568966325   786 GLPTDAKIFVRVKAINAAGASEP 808
Cdd:pfam00041   62 GLKPGTEYEVRVQAVNGGGEGPP 84

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 568966325   823 PPKIRIPrhlKQTYIRRVGEAVNLVIPFQGKPRPELTWKKDGEEIDKN-QINIRNSETDTIIFIRKAERSHSGKY 896
Cdd:pfam13927    1 KPVITVS---PSSVTVREGETVTLTCEATGSPPPTITWYKNGEPISSGsTRSRSLSGSNSTLTISNVTRSDAGTY 72

Immunoglobulin like; IG domains that cannot be classified into one of IGv1, IGc1, IGc2, IG.

                            10        20        30        40        50        60        70        80
                    ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325    834 QTYIRRVGEAVNLVIPFQGKPRPELTWKKDGEE--IDKNQINIRNSETDTIIFIRKAERSHSGKYDLQVKVDKYVENASI 911
Cdd:smart00410    2 PSVTVKEGESVTLSCEASGSPPPEVTWYKQGGKllAESGRFSVSRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSGT 81

                    ....
gi 568966325    912 DIQI 915
Cdd:smart00410   82 TLTV 85

Fourth immunoglobulin (Ig)-like domain of hemolin, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the fourth immunoglobulin (Ig)-like domain of hemolin and similar proteins. Hemolin, an insect immunoglobulin superfamily (IgSF) member containing four Ig-like domains, is a lipopolysaccharide-binding immune protein induced during bacterial infection. Hemolin shares significant sequence similarity with the first four Ig-like domains of the transmembrane cell adhesion molecules (CAMs) of the L1 family. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. The fourth Ig-like domain of hemolin is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set domains, members of the I-set have a discontinuous A strand but lack a C" strand. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 568966325  419 PLKITTPLTDQTVKLGKEVCLKCEISENVPGK--WTKNGLPVQEGERLKVVHKGRihkLVIANALIEDEGEY 488
Cdd:cd20978     1 PKFIQKPEKNVVVKGGQDVTLPCQVTGVPQPKitWLHNGKPLQGPMERATVEDGT---LTIINVQPEDTGYY 69

Immunoglobulin like; IG domains that cannot be classified into one of IGv1, IGc1, IGc2, IG.

                            10        20        30        40        50        60        70        80
                    ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325    247 PAYQVDKGGKVRFVVEL-ADPKLEVKWFKNGQE-IRPSTKYIFEHKGNERIMFINNCSLTDDSEYYVTA----GDEKCST 320
Cdd:smart00410    2 PSVTVKEGESVTLSCEAsGSPPPEVTWYKQGGKlLAESGRFSVSRSGSTSTLTISNVTPEDSGTYTCAAtnssGSASSGT 81

                    ....
gi 568966325    321 ELFV 324
Cdd:smart00410   82 TLTV 85

Immunoglobulin Domain C1 of human cardiac Myosin Binding Protein C and similar proteins; a member of the I-set of IgSF domains; The members here are composed of the immunoglobulin domain C1 of human cardiac Myosin Binding Protein C (MyBP-C). MyBP-C is a thick filament protein involved in the regulation of muscle contraction. Mutations in cardiac MyBP-C gene are the second most frequent cause of hypertrophic cardiomyopathy. MyBP-C binds to myosin with two binding sites, one at its C-terminus and another at its N-terminus. The N-terminal binding site, consisting of immunoglobulin (lg) domains C1 and C2 connected by a flexible linker, interacts with the S2 segment of myosin in a phosphorylation-regulated manner. The C1 and C2 Ig domains can bind to and activate or inhibit the thin filament. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. The C1 domain of the MyBP-C is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand but lack a C" strand. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325   46 LFVEKPQTGSVKVGANITFVAKVRAEDLLRKPTVKWFKGKWMDLASKAGKHLQLKETFERQTRVYTFEMQIIKAKENYAG 125
Cdd:cd20962     1 LFVMRPQDGEVTVGGSITFSARVAGASLLKPPVVKWFKGKWVDLSSKVGQHLQLHDSYDRASKVYLFELHITDAQPAFAG 80

                          90       100
                  ....*....|....*....|.
gi 568966325  126 NYRCEVTYKDKFDSCSFDLEV 146
Cdd:cd20962    81 GYRCEVSTKDKFDCSNFNLTV 101

Domain C2 of human cardiac Myosin Binding Protein C and similar domains; a member of the I-set of IgSF domains; The members here are composed of the immunoglobulin (Ig) Domain C2 of human cardiac Myosin Binding Protein C (MyBP-C) and similar domains. MyBP-C is a thick filament protein involved in the regulation of muscle contraction. Mutations in cardiac MyBP-C gene are the second most frequent cause of hypertrophic cardiomyopathy. MyBP-C binds to myosin with two binding sites, one at its C-terminus and another at its N-terminus. The N-terminal binding site, consisting of immunoglobulin (lg) domains C1 and C2 connected by a flexible linker, interacts with the S2 segment of myosin in a phosphorylation-regulated manner. The C1 and C2 Ig domains can bind to and activate or inhibit the thin filament. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Unlike the V-set, one of the distinctive features of I-set domains is the lack of a C" strand. The structures of the Ig domains of MyBP-C lack this strand and thus belong to the I-set of Ig superfamily domains. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325  243 KILDPAYQVDKGGKVRFVVELADPKLEVKWFKNGQEIRPSTKYIFEHKGNERIMFINNCSLTDDSEYYVTAGDEKCSTEL 322
Cdd:cd20967     1 KKAQPAVQVSKGHKIRLTVELADPDAEVKWYKDGQELQSSSKVIFESIGAKRTLTVQQASLADAGEYQCVAGGEKCSFEL 80

                  ..
gi 568966325  323 FV 324
Cdd:cd20967    81 FV 82

Immunoglobulin (Ig)-like domain of titin and similar proteins; The members here are composed of the immunoglobulin (Ig)-like domain found in titin-like proteins and similar proteins. Titin (also called connectin) is a fibrous sarcomeric protein specifically found in vertebrate striated muscle. Titin is a giant protein; depending on isoform composition, it ranges from 2970 to 3700 kDa, and is of a length that spans half a sarcomere. Titin largely consists of multiple repeats of Ig-like and fibronectin type 3 (FN-III)-like domains. Titin connects the ends of myosin thick filaments to Z disks and extends along the thick filament to the H zone. It appears to function similarly to an elastic band, keeping the myosin filaments centered in the sarcomere during muscle contraction or stretching. Within the sarcomere, titin is also attached to or is associated with myosin binding protein C (MyBP-C). MyBP-C appears to contribute to the generation of passive tension by titin and like titin has repeated Ig-like and FN-III domains. Also included in this group are worm twitchin and insect projectin, thick filament proteins of invertebrate muscle which also have repeated Ig-like and FN-III domains.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 568966325  835 TYIRRVGEAVNLVIPFQGKPRPELTWKKDGEEIDKNQ-INIRNSETDTIIFIRKAERSHSGKYDLQVK 901
Cdd:cd05748     1 TIVVRAGESLRLDIPIKGRPTPTVTWSKDGQPLKETGrVQIETTASSTSLVIKNAKRSDSGKYTLTLK 68

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 568966325  1034 PMFTQPLVNTYAIAGYNATLNCSVRGNPKPKITWMKNKVAIVDDPRYRMFSNQGVCTLEIRKPSPYDGGTYCCKAVN 1110
Cdd:pfam13927    2 PVITVSPSSVTVREGETVTLTCEATGSPPPTITWYKNGEPISSGSTRSRSLSGSNSTLTISNVTRSDAGTYTCVASN 78

Immunoglobulin domain; The members here are composed of the immunoglobulin (Ig) domain found in the Ig superfamily. The Ig superfamily is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. Members of this group are components of immunoglobulin, neuroglia, cell surface glycoproteins, including T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins, including butyrophilin and chondroitin sulfate proteoglycan core protein. A predominant feature of most Ig domains is a disulfide bridge connecting the two beta-sheets with a tryptophan residue packed against the disulfide bond. Ig superfamily (IgSF) domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Typically, the V-set domains have A, B, E, and D strands in one sheet and A', G, F, C, C' and C" in the other. The structures in C1-set are smaller than those in the V-set; they have one beta sheet that is formed by strands A, B, E, and D and the other by strands G, F, C, and C'. Moreover, a C1-set Ig domain contains a short C' strand (three residues) and lacks A' and C" strand. Unlike other Ig domain sets, C2-set structures do not have a D strand. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

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gi 568966325 1051 ATLNCSVRGNPKPKITWMKNKVAIVDDPRYRMFSNQGVCTLEIRKPSPYDGGTYCCKAVNDLGTVE 1116
Cdd:cd00096     1 VTLTCSASGNPPPTITWYKNGKPLPPSSRDSRRSELGNGTLTISNVTLEDSGTYTCVASNSAGGSA 66

Fibronectin type 3 domain; One of three types of internal repeat within the plasma protein, fibronectin. The tenth fibronectin type III repeat contains a RGD cell recognition sequence in a flexible loop between 2 strands. Type III modules are present in both extracellular and intracellular proteins.

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                    ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325    919 PGPPQTVTIEDVWGENVALTWTPPKDDGNAA-ITGYTIQKaDKKSMEWFTVIEHYHRTNATITELVIGNEYYFRVFAENM 997
Cdd:smart00060    1 PSPPSNLRVTDVTSTSVTLSWEPPPDDGITGyIVGYRVEY-REEGSEWKEVNVTPSSTSYTLTGLKPGTEYEFRVRAVNG 79

                    ....
gi 568966325    998 CGLS 1001
Cdd:smart00060   80 AGEG 83

Immunoglobulin domain I1 of the titin I-band and similar proteins; a member of the I-set of IgSF domains; The members here are composed of the immunoglobulin domain I1 of the titin I-band and similar proteins. Titin is a key component in the assembly and functioning of vertebrate striated muscles. By providing connections at the level of individual microfilaments, it contributes to the fine balance of forces between the two halves of the sarcomere. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. The two sheets are linked together by a conserved disulfide bond between B strand and F strand. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. The Ig I1 domain of the titin I-band is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand but lack a C" strand. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325 1047 AGYNATLNCSVRGNPKPKITWMKNKVAI---VDDPRYRMFSNQGVCTLEIRKPSPYDGGTYCCKAVNDLGTVEIECKLEV 1123
Cdd:cd20951    14 EKSDAKLRVEVQGKPDPEVKWYKNGVPIdpsSIPGKYKIESEYGVHVLHIRRVTVEDSAVYSAVAKNIHGEASSSASVVV 93

                  .
gi 568966325 1124 K 1124
Cdd:cd20951    94 E 94

immunoglobulin-like domain of telokin and similar proteins; a member of the I-set of IgSF domains; The members here are composed of the immunoglobulin (Ig) domain in telokin, the C-terminal domain of myosin light chain kinase which is identical to telokin, and similar proteins. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Unlike the V-set, one of the distinctive features of I-set domains is the lack of a C" strand. The structure of the telokin Ig domain lacks this strand and thus it belongs to the I-set of the IgSF. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568966325 1037 TQPLVNTYAIAGYNATLNCSVRGNPKPKITWMKNKVAIVDDPRYRM-FSNQGVCTLEIRKPSPYDGGTYCCKAVNDLGTV 1115
Cdd:cd20973     1 IQTLRDKEVVEGSAARFDCKVEGYPDPEVKWMKDDNPIVESRRFQIdQDEDGLCSLIISDVCGDDSGKYTCKAVNSLGEA 80

                  ....*...
gi 568966325 1116 EIECKLEV 1123
Cdd:cd20973    81 TCSAELTV 88