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cistern family PEP-CTERM protein Members of this family are PEP-CTERM proteins, that is, surface proteins of Gram-negative organisms that carry a short C-terminal region used to help target proteins to their proper cellular location, hold them in position for post-translational modifications that might need to occur (such as glycosylation), and which is eventually removed by exosortase as the protein is ligated to something else. In this family the most conspicuous feature other than the PEP-CTERM sorting signal (with variants that include PEP, PAP, PTP, and SEP) is a pair of Cys residues about 6 amino acids apart from each other. The second Cys occurs in the middle of run of amino acids that are all either small (Gly, Ser, Ala) or else Asn. The local context suggests the Cys occurs at a turn at the end of a structural feature such as alpha-helix or beta-strand, rather than in the middle of one. The word "cistern" was assigned to suggest the proposed Cys-turn feature. |
Lu S et al.(2020). "CDD/SPARCLE: the conserved domain database in 2020.",