3vy7
From Proteopedia
Crystal structure of human pancreatic secretory protein ZG16p with O-(alpha-D-mannosyl)-L-serine
Structural highlights
FunctionZG16_HUMAN May play a role in protein trafficking. May act as a linker molecule between the submembranous matrix on the luminal side of zymogen granule membrane (ZGM) and aggregated secretory proteins during granule formation in the TGN.[1] Publication Abstract from PubMedZG16p is a soluble mammalian lectin, the first to be described with a Jacalin-related beta-prism-fold. ZG16p has been reported to bind both to glycosaminoglycans and mannose. To determine the structural basis of the multiple sugar-binding properties, we conducted glycan microarray analyses of human ZG16p. We observed that ZG16p preferentially binds to alpha-mannose-terminating short glycans such as Ser/Thr-linked O-mannose, but not to high mannose-type N-glycans. Among sulfated glycosaminoglycan oligomers examined, chondroitin sulfate B and heparin oligosaccharides showed significant binding. Crystallographic studies of human ZG16p lectin in the presence of selected ligands revealed the mechanism of multiple sugar recognition. Manalpha1-3Man and Glcbeta1-3Glc bound in different orientations: the nonreducing end of the former and the reducing end of the latter fitted in the canonical shallow mannose binding pocket. Solution NMR analysis using (15)N-labeled ZG16p defined the heparin-binding region, which is on an adjacent flat surface of the protein. On-array competitive binding assays suggest that it is possible for ZG16p to bind simultaneously to both types of ligands. Recognition of a broad spectrum of ligands by ZG16p may account for the multiple functions of this lectin in the formation of zymogen granules via glycosaminoglycan binding, and in the recognition of pathogens in the digestive system through alpha-mannose-related recognition. Structural Basis for Multiple Sugar Recognition of Jacalin-related Human ZG16p Lectin.,Kanagawa M, Liu Y, Hanashima S, Ikeda A, Chai W, Nakano Y, Kojima-Aikawa K, Feizi T, Yamaguchi Y J Biol Chem. 2014 Jun 13;289(24):16954-65. doi: 10.1074/jbc.M113.539114. Epub, 2014 Apr 30. PMID:24790092[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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