5kdx
IMPa metallopeptidase in complex with T-antigen
Structural highlights
FunctionIMPA_PSEAE Protease that degrades several proteins of the host immune system. Cleaves P-selectin glycoprotein ligand-1 (PSGL-1), leading to its functional inhibition; PSGL-1 is a leukocyte cell-surface receptor essential for leukocyte recruitment to the site of infection. Next to PSGL-1, targets host CD43 and CD44 that are also involved in leukocyte homing. Thus, prevents neutrophil extravasation and thereby protects P.aeruginosa from neutrophil attack. Is also able to inhibit the decay accelerating factor (CD55), but not the cell-surface receptors CD46 and CD31.[1] Publication Abstract from PubMedThe vast majority of proteins are posttranslationally altered, with the addition of covalently linked sugars (glycosylation) being one of the most abundant modifications. However, despite the hydrolysis of protein peptide bonds by peptidases being a process essential to all life on Earth, the fundamental details of how peptidases accommodate posttranslational modifications, including glycosylation, has not been addressed. Through biochemical analyses and X-ray crystallographic structures we show that to hydrolyze their substrates, three structurally related metallopeptidases require the specific recognition of O-linked glycan modifications via carbohydrate-specific subsites immediately adjacent to their peptidase catalytic machinery. The three peptidases showed selectivity for different glycans, revealing protein-specific adaptations to particular glycan modifications, yet always cleaved the peptide bond immediately preceding the glycosylated residue. This insight builds upon the paradigm of how peptidases recognize substrates and provides a molecular understanding of glycoprotein degradation. Recognition of protein-linked glycans as a determinant of peptidase activity.,Noach I, Ficko-Blean E, Pluvinage B, Stuart C, Jenkins ML, Brochu D, Buenbrazo N, Wakarchuk W, Burke JE, Gilbert M, Boraston AB Proc Natl Acad Sci U S A. 2017 Jan 17. pii: 201615141. doi:, 10.1073/pnas.1615141114. PMID:28096352[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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