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PapD-like superfamily
SCOP classification
InterPro annotation
| Cross references | IPR008962 SSF49354 Protein matches |
| Abstract | The PapD-like superfamily of periplasmic chaperones directs the assembly of over 30 diverse adhesive surface organelles that mediate the attachment of many different pathogenic bacteria to host tissues, a critical early step in the development of disease. PapD, the prototypical chaperone, is necessary for the assembly of P pili. P pili contain the adhesin PapG, which mediates the attachment of uropathogenic Escherichia coli to Gal(alpha) Gal receptors present on kidney cells and are critical for the initiation of pyelonephritis. The PapD-like chaperones consist of two Ig-like domains oriented toward each other, forming L-shaped molecules. In the chaperone-subunit complex, the G1beta strand of the chaperone completes an atypical Ig fold in the subunit by occupying the groove and running parallel to the subunit C-terminal F strand. This donor strand complementation interaction simultaneously stabilizes pilus subunits and caps their interactive surfaces, preventing their premature oligomerisation in the periplasm. During pilus biogenesis, the highly conserved N-terminal extension of one subunit has been proposed to displace the chaperone G1beta strand from its neighbouring subunit in a mechanism termed donor strand exchange [ 10859353].
This entry represents the immunoglobulin (Ig)-like beta-sandwich domain found in PapD, as well as in other periplasmic chaperone proteins that include FimC and SfaE from Escherichia coli, and Caf1m from Yersinia pestis [15372038]. In addition, major sperm proteins (MSP) and other related sperm proteins (such as WR4 and SSP-19) contain an Ig-like domain with a similar structural fold to PapD [12051923, 15388931]. Major sperm proteins are central components in molecular interactions underlying sperm motility, with many isoforms existing in Caenorhabditis elegans.
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InterPro database
Functional annotation
| General category | Processes_IC |
| Detailed category | Protein modification |
Function annotation of SCOP domain superfamilies
Jump to [ Top of page · SCOP classification · InterPro annotation · Functional annotation ]
Internal database links
The SUPERFAMILY hidden Markov model library has been used to carry
out SCOP domain assignments to all genomes at the superfamily level. Click on the 'Genome Assignments'
icon above to view the genome assignments for this superfamily.
Alignments of sequences to Alignments of sequences to 9 models
in this superfamily are available by clicking on the superfamily level 'Alignments' icon above. PDB sequences less than 40% identical
are shown by default, but any other sequences may be aligned. Select PDB sequences, genome sequences, or paste in or upload your own.
It is possible to browse and view the proteins in the genomes which have
different combinations of domains including a PapD-like domain. Click on the 'Domain Combinations' icon.
To view the distribution of domain superfamilies, or families, across the major taxonomic kingdoms or genomes within a kingdom click on the 'TaxViz' icon above. This gives an immediate impression of how superfamilies, or families, are restricted to certain kingdoms of life.
Undirected domain occurrence networks are available for all superfamilies. Nodes in these networks represent genomes. Connections between nodes represent the presence of domain architectures, which contain the superfamily of interest, in both genomes.
There are 9 hidden Markov models representing the PapD-like superfamily. Information on how the models are built, and plots showing hydrophobicity, match emmission probabilities and insertion/deletion probabilities can be viewed by clicking on the icon above.
Jump to [ Top of page · SCOP classification · InterPro annotation · Functional annotation · Internal database links ]
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