PIN (PilT N terminus) domain: Superfamily; The PIN (PilT N terminus) domain belongs to a large nuclease superfamily, and were originally named for their sequence similarity to the N-terminal domain of an annotated pili biogenesis protein, PilT, a domain fusion between a PIN-domain and a PilT ATPase domain. The structural properties of the PIN domain indicate its active center, consisting of three highly conserved catalytic residues which coordinate metal ions; in some members, additional metal coordinating residues can be found while some others lack several of these key catalytic residues. The PIN active site is geometrically similar in the active center of structure-specific 5' nucleases, PIN-domain ribonucleases of eukaryotic rRNA editing proteins, and bacterial toxins of toxin-antitoxin (TA) operons. The PIN domain superfamily includes: the FEN-like PIN domain family such as the PIN domains of Flap endonuclease-1 (FEN1), exonuclease-1 (EXO1), Mkt1, Gap Endonuclease 1 (GEN1), and Xeroderma pigmentosum complementation group G (XPG) nuclease, 5'-3' exonucleases of DNA polymerase I and bacteriophage T4- and T5-5' nucleases; the VapC-like PIN domain family which includes toxins of prokaryotic toxin/antitoxin operons FitAB and VapBC, as well as eukaryotic ribonucleases such as Smg6, ribosome assembly factor NOB1, exosome subunit Rrp44 endoribonuclease and rRNA-processing protein Fcf1; the LabA-like PIN domain family which includes the PIN domains of Synechococcus elongatus LabA (low-amplitude and bright); the PRORP-Zc3h12a-like PIN domain family which includes the PIN domains of RNase P (PRORP), ribonuclease Zc3h12a; and Bacillus subtilis YacP/Rae1-like PIN domains. It also includes the Mut7-C PIN domain family, which is not represented here as it is a shortened version of the PIN fold and lacks a core strand and helix (H3 and S3). The Mut7-C PIN domain family includes the C-terminus of Caenorhabditis elegans exonuclease Mut-7.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 489507535   8 VLVDTSVAVAPVVADHDHHEDTFQALRGRTLGLAGHAAFE------------RRTLATVAKLLAHTFPATRFLGAGAAMS 75
Cdd:cd18681    1 IAVDTSVAVALLVSWHEAHEAARAALRGRRLGLAGHAAFEtysvltrlppphRVAPADAARLLAANFPESLTLSATAYAA 80

                         90
                 ....*....|....*
gi 489507535  76 LLPELAPAEIAGGAV 90
Cdd:cd18681   81 LLPELAAAGISGGAV 95

VapC-like PIN domain of Mycobacterium tuberculosis VapC27, and VapC40, and related proteins; This subfamily includes Mycobacterium tuberculosis VapC27 and VapC40. It belongs to the VapC (virulence-associated protein C)-like family of the PIN domain nuclease superfamily. VapC is the PIN-domain ribonuclease toxin from prokaryotic VapBC toxin-antitoxin (TA) systems. VapB is a transcription factor-like protein antitoxin acting as an inhibitor. Other members of the VapC-like nuclease family include FitB toxin of the FitAB TA system, eukaryotic ribonucleases such as Smg6, ribosome assembly factor NOB1, exosome subunit Rrp44 endoribonuclease and rRNA-processing protein Fcf1. The structural properties of the PIN (PilT N terminus) domain indicate its active center, consisting of three highly conserved catalytic residues which coordinate metal ions, in some members, additional metal coordinating residues can be found. Some members of the superfamily lack several of these key catalytic residues. The PIN active site is geometrically similar in the active center of structure-specific 5' nucleases, PIN-domain ribonucleases of eukaryotic rRNA editing proteins, and bacterial toxins of toxin-antitoxin (TA) operons.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 489507535   8 VLVDTSVAVAPVVADHDHHEDTFQALRGRTLGLAGHAAFE------------RRTLATVAKLLAHTFPATRFLGAGAAMS 75
Cdd:cd18681    1 IAVDTSVAVALLVSWHEAHEAARAALRGRRLGLAGHAAFEtysvltrlppphRVAPADAARLLAANFPESLTLSATAYAA 80

                         90
                 ....*....|....*
gi 489507535  76 LLPELAPAEIAGGAV 90
Cdd:cd18681   81 LLPELAAAGISGGAV 95

VapC-like PIN domain of Mycobacterium tuberculosis VapC27, and VapC40, and related proteins; This subfamily includes Mycobacterium tuberculosis VapC27 and VapC40. It belongs to the VapC (virulence-associated protein C)-like family of the PIN domain nuclease superfamily. VapC is the PIN-domain ribonuclease toxin from prokaryotic VapBC toxin-antitoxin (TA) systems. VapB is a transcription factor-like protein antitoxin acting as an inhibitor. Other members of the VapC-like nuclease family include FitB toxin of the FitAB TA system, eukaryotic ribonucleases such as Smg6, ribosome assembly factor NOB1, exosome subunit Rrp44 endoribonuclease and rRNA-processing protein Fcf1. The structural properties of the PIN (PilT N terminus) domain indicate its active center, consisting of three highly conserved catalytic residues which coordinate metal ions, in some members, additional metal coordinating residues can be found. Some members of the superfamily lack several of these key catalytic residues. The PIN active site is geometrically similar in the active center of structure-specific 5' nucleases, PIN-domain ribonucleases of eukaryotic rRNA editing proteins, and bacterial toxins of toxin-antitoxin (TA) operons.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 489507535   8 VLVDTSVAVAPVVADHDHHEDTFQALRGRTLGLAGHAAFE------------RRTLATVAKLLAHTFPATRFLGAGAAMS 75
Cdd:cd18681    1 IAVDTSVAVALLVSWHEAHEAARAALRGRRLGLAGHAAFEtysvltrlppphRVAPADAARLLAANFPESLTLSATAYAA 80

                         90
                 ....*....|....*
gi 489507535  76 LLPELAPAEIAGGAV 90
Cdd:cd18681   81 LLPELAAAGISGGAV 95