4ou3 | pdb_00004ou3
Crystal structure of porcine aminopeptidase N complexed with CNGRCG tumor-homing peptide
Structural highlights
FunctionAMPN_PIG Broad specificity aminopeptidase. Plays a role in the final digestion of peptides generated from hydrolysis of proteins by gastric and pancreatic proteases. May be involved in the metabolism of regulatory peptides of diverse cell types, responsible for the processing of peptide hormones, such as angiotensin III and IV, neuropeptides, and chemokines and involved the cleavage of peptides bound to major histocompatibility complex class II molecules of antigen presenting cells. May have a role in angiogenesis (By similarity). It is able to degrade Leu-enkephalin and Met-enkephalin but not cholecystokinin CCK8, neuromedin C (GRP-10), somatostatin-14, substance P and vasoactive intestinal peptide. In case of porcine transmissible gastroenteritis coronavirus (TGEV) and porcine respiratory coronavirus (PRCoV) infections, serves as a receptor for TGEV and PRCoV spike glycoprotein in a species-specific manner.[1] [2] [3] [4] [5] Publication Abstract from PubMedTumor cell surface aminopeptidase N (APN or CD13) has two puzzling functions unrelated to its enzymatic activity: mediating tumor cell motility and serving as a receptor for tumor-homing peptides (peptides that bring anti-cancer drugs to tumor cells). To investigate APN-based tumor-homing therapy, we determined the crystal structure of APN complexed with a tumor-homing peptide containing a representative Asn-Gly-Arg (NGR) motif. The tumor-homing peptide binds to the APN enzymatic active site, but resists APN degradation due to a distorted scissile peptide bond. To explore APN-based tumor cell motility, we examined the interactions between APN and extracellular matrix (ECM) proteins. APN binds to, but does not degrade, NGR motifs in ECM proteins that share similar conformations with the NGR motif in the APN-bound tumor-homing peptide. Therefore, APN-based tumor cell motility and tumor-homing therapy rely on a unified mechanism in which both functions are driven by the specific and stable interactions between APN and the NGR motifs in ECM proteins and tumor-homing peptides. This study further implicates APN as an integrin-like molecule that functions broadly in cell motility and adhesion via interacting with its signature NGR motif in the extracellular environment. A unified mechanism for aminopeptidase N-based tumor cell motility and tumor-homing therapy.,Liu C, Yang Y, Chen L, Lin YL, Li F J Biol Chem. 2014 Oct 29. pii: jbc.M114.566802. PMID:25359769[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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