Saf-pilin pilus formation protein; This domain consists of the adjacent Saf-Nte and Saf-pilin chains of the pilus-forming complex. Pilus assembly in Gram-negative bacteria involves a Donor-strand exchange mechanism between the C- and the N-termini of this domain. The C-terminal subunit forms an incomplete Ig-fold which is then complemented by the 10-18 residue N-terminus of another, incoming, pilus subunit which is not involved in the Ig-fold. The N-terminus sequences contain a motif of alternating hydrophobic residues that occupy the P2 to P5 binding pockets in the groove of the first pilus subunit.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 446189075   31 AEKLQTTLRVGAYFRAGHVPDGMVLAQGWVTYHGSHSGFRVWSDEQKAGNTPTVLLLSGQQDPRHHIQVRLEGEGWQPDT 110
Cdd:pfam09460  22 AEKLQLILRSGLKAGAGAPPAGIAKAQGNSTTHGEFGGFGISNDEQDAGGTATRLAGKGQGDEIGHGLSRDEGEGSDPDE 101

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|.
gi 446189075  111 VSGRGAILRTAADNASFSVVVDGNQEVPADTWTLDFKACAL 151
Cdd:pfam09460 102 KSGGGAILRFAADDALDIVLTDGAQEVPADTWPIDFDACAL 142

Saf-pilin pilus formation protein; This domain consists of the adjacent Saf-Nte and Saf-pilin chains of the pilus-forming complex. Pilus assembly in Gram-negative bacteria involves a Donor-strand exchange mechanism between the C- and the N-termini of this domain. The C-terminal subunit forms an incomplete Ig-fold which is then complemented by the 10-18 residue N-terminus of another, incoming, pilus subunit which is not involved in the Ig-fold. The N-terminus sequences contain a motif of alternating hydrophobic residues that occupy the P2 to P5 binding pockets in the groove of the first pilus subunit.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 446189075   31 AEKLQTTLRVGAYFRAGHVPDGMVLAQGWVTYHGSHSGFRVWSDEQKAGNTPTVLLLSGQQDPRHHIQVRLEGEGWQPDT 110
Cdd:pfam09460  22 AEKLQLILRSGLKAGAGAPPAGIAKAQGNSTTHGEFGGFGISNDEQDAGGTATRLAGKGQGDEIGHGLSRDEGEGSDPDE 101

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|.
gi 446189075  111 VSGRGAILRTAADNASFSVVVDGNQEVPADTWTLDFKACAL 151
Cdd:pfam09460 102 KSGGGAILRFAADDALDIVLTDGAQEVPADTWPIDFDACAL 142

AfaD and similar proteins; This subfamily consists of Escherichia coli AfaD, Salmonella SafD, and similar proteins. The afa gene clusters encode an afimbrial adhesive sheath produced by Escherichia coli. The adhesive sheath is composed of two proteins, AfaD and AfaE, which are independently exposed at the bacterial cell surface. AfaE is required for bacterial adhesion to HeLa cells and AfaD for the uptake of adherent bacteria into these cells. SafD is the minor subunit of Saf pili, which are often found in clinical isolates of Salmonella and are assembled by the chaperone-usher secretion pathway. In addition to safD, the saf operon is also composed of safA (major subunit), safB (periplasmic chaperone), and safC (outer membrane usher). Also included is the enteroaggregative Escherichia coli AAF/IV pilus tip protein, which is implicated in adhesion as well. During fimbria/pili assembly, polymerization occurs when the N-terminal extension (NTE) of one monomer is inserted into an adjacent monomer, providing the final beta strand or G-strand, to complete the Ig-like fold, in a mechanism called the donor-strand complementation (DSC) or donor-strand exchange (DSE).

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 446189075  34 LQTTLRVGAYFRAGHVPDGMVLAQGWVTYHGSHSGFRVWSDEQKAGNTPTVLLLSGQQDPRHHIQVRLEGEGWQPDTVSG 113
Cdd:cd18776    1 LELSLQPKTGLGAGLVRDGTLIATGRISCRGAHSGFRVWSNAEKVGGRPGRYILTGKNNPRNKLRVRLEGEGWQPDTQGG 80

                         90       100       110
                 ....*....|....*....|....*....|....*...
gi 446189075 114 RGAILRTAADNASFSVVVDGNQEVPADTWTLDFKACAL 151
Cdd:cd18776   81 KGIILTTSEESATFDIVADGNQNVPPDTYTISLSAACL 118

AfaD-like family of invasins; This family consists of Escherichia coli AfaD, Salmonella SafA and SafD, Yersinia pestis PsaA, Yersinia enterocolitica MyfA, and similar proteins. The afa gene clusters encode an afimbrial adhesive sheath produced by Escherichia coli. The adhesive sheath is composed of two proteins, AfaD and AfaE, which are independently exposed at the bacterial cell surface. AfaE is required for bacterial adhesion to HeLa cells and AfaD for the uptake of adherent bacteria into these cells. Saf-pilin pilus formation proteins SafA and SafD are the major and minor subunits, respectively, of Saf pili, which are often found in clinical isolates of Salmonella and are assembled by the chaperone-usher secretion pathway. PsaA and MyfA are the major subunits of pH 6 antigen (Psa) and Myf fimbrial homopolymers. Also included is the enteroaggregative Escherichia coli AAF/IV pilus tip protein, which is implicated in adhesion as well. During fimbria/pili assembly, polymerization occurs when the N-terminal extension (NTE) of one AfaD-like family monomer is inserted into an adjacent monomer, providing the final beta strand or G-strand, to complete the Ig-like fold, in a mechanism called the donor-strand complementation (DSC) or donor-strand exchange (DSE).

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 446189075  43 YFRAGHVPDGMVLAQGWVTYHGSHSGFRVWSDE--QKAGNTPTVLLLSGQQDpRHHIQVRLEGEGWQPDTVSGRGAILRT 120
Cdd:cd16911   10 GLGAGTQPDGTKIATLSVTNTGSHGGWRVYTNPnsVDGVGGAKGYTVRSKDG-SKKVGVRIGGDGYSGVKGGGGNWVGTG 88

                         90       100
                 ....*....|....*....|....*
gi 446189075 121 A-ADNASFSVVVDGNQEVPADTWTL 144
Cdd:cd16911   89 PtTKYITFDIVTDGGQQVKAGTYLF 113

Saf-pilin pilus formation protein SafA; This subfamily is composed of Saf-pilin pilus formation protein SafA from Salmonella enterica and similar proteins. SafA is the major subunit of Saf pili, which are often found in clinical isolates of Salmonella and are assembled by the chaperone-usher secretion pathway. In addition to safA, the saf operon is also composed of safB (periplasmic chaperone), safC (outer membrane usher), and safD (minor subunit). SafA and SafD subunits are transported from the cytoplasm into the periplasm via the SEC machinery, and the periplasmic chaperone SafB donates its G1 strand to complete the correct folding of SafA or SafD. In Saf pili assembly, the N-terminal extension (NTE) of an incoming SafA replaces the G1 strand (in SafB) via a zip-in-zip-out mechanism (also called donor-strand complementation or exchange) to form the polymer of SafD-(SafA)n (n > 100).

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 446189075  46 AGHVPDGMVLAQGWVTY-HGSHSGFRvWSDEQKAGNTPTVLLLSGQQDpRHHIQVRLEGEGWQPDTVSGRG---AILRTA 121
Cdd:cd18775   13 AGKHADNTVIAKGTVTStDAKRFAVR-GTAGTGEDSNGSAWTITGKND-GNKLKVKLSPDSTSGSTVKWNGgtwFVFNIN 90

                         90       100
                 ....*....|....*....|...
gi 446189075 122 ADNASFSVVVDGNQEVPADTWTL 144
Cdd:cd18775   91 APTDTYDIKLDGDQNVPADTYPI 113