3aqg

Publication Abstract from PubMed

ZG16p is a secretory protein that mediates condensation-sorting of pancreatic enzymes to the zymogen granule membrane in pancreatic acinar cells. ZG16p interacts with glycosaminoglycans and the binding is considered to be important for condensation-sorting of pancreatic enzymes. ZG16b/PAUF, a paralog of ZG16p, has recently been found to play a role in gene regulation and cancer metastasis. However, the detailed functions of ZG16p and ZG16b remain to be clarified. Here, in order to obtain insights into structure-function relationships, we conducted crystallographic studies of human ZG16p lectin as well as its paralog, ZG16b, and determined their crystal structures at 1.65 and 2.75A resolution, respectively. ZG16p has a Jacalin-related beta-prism fold, the first to be reported among mammalian lectins. The putative sugar-binding site of ZG16p is occupied by a glycerol molecule, mimicking the mannose bound to Jacalin-related mannose-binding-type plant lectins such as Banlec. ZG16b also has a beta-prism fold, but some amino acid residues of the putative sugar-binding site differ from those of the mannose-type binding site suggesting altered preference. A positively charged patch, which may bind sulfated groups of the glycosaminoglycans, is located around the putative sugar-binding site of ZG16p and ZG16b. Taken together, we suggest that the sugar-binding site and the adjacent basic patch of ZG16p and ZG16b cooperatively form a functional glycosaminoglycan-binding site.

Crystal structures of human secretory proteins ZG16p and ZG16b reveal a Jacalin-related beta-prism fold.,Kanagawa M, Satoh T, Ikeda A, Nakano Y, Yagi H, Kato K, Kojima-Aikawa K, Yamaguchi Y Biochem Biophys Res Commun. 2010 Nov 24. PMID:21110947^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.