PSA

Paramecium Surface Antigen Repeat
PSA
SMART accession number:SM00639
Description: -
Interpro abstract (IPR002895):

The G surface protein of Paramecium primaurelia has important internal homologies and a periodic structure, which could be dictated in part by the rigid scaffolding of cysteine residues. The predicted secondary structure shows a quasi absence of alpha-helix and an abundance of beta-pleated sheets and random coils. The monotony of the amino acid sequence is in favour of a structural role for the protein [ (PUBMED:3783679) ]. This structure is based on the presence of 37 periods of about 75 residues, each period containing eight cysteine residues [ (PUBMED:2308165) ]. Homologies with other proteins are limited to surface antigens of trypanosomes.

Family alignment:
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There are 2198 PSA domains in 139 proteins in SMART's nrdb database.

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