title: Crystal structure of Korean pine (Pinus koraiensis) 7S seed storage protein with copper ligands.
abstract: The prevalence of food allergy has increased in recent years, and Korean pine vicilin is a potential food allergen. We have previously reported the crystallization of Korean pine vicilin purified from raw pine nut. Here we report the isolation of vicilin mRNA and the crystal structure of Korean pine vicilin at 2.40 Å resolution. The overall structure of pine nut vicilin is similar to the structures of other 7S seed storage proteins and consists of an N-terminal domain and a C-terminal domain. Each assumes a cupin fold, and they are symmetrically related about a pseudodyad axis. Three vicilin molecules form a doughnut-shaped trimer through head-to-tail association. Structure characterization of Korean pine nut vicilin unexpectedly showed that, in its native trimeric state, the vicilin has three copper ligands. Sequence alignments suggested that the copper-coordinating residues were conserved in winter squash, sesame, tomato, and several tree nuts, while they were not conserved in a number of legumes, including peanut and soybean. Additional studies are needed to assess whether the copper-coordinating property of vicilins has a biological function in the relevant plants. The nutritional value of this copper-coordinating protein in tree nuts and other edible seeds may be worth further investigations.
authors: Department of Biology, Illinois Institute of Technology , 3101 South Dearborn Street, Chicago, Illinois 60616, United States.
authors: Tengchuan
authors: T
authors: Jin
authors: Yang
authors: Y
authors: Wang
authors: Yu-Wei
authors: YW
authors: Chen
authors: Tong-Jen
authors: TJ
authors: Fu
authors: Mahendra H
authors: MH
authors: Kothary
authors: Tara H
authors: TH
authors: McHugh
authors: Yuzhu
authors: Y
authors: Zhang
mesh_terms: D001665:Binding Sites; D003300:Copper / Q000737:chemistry* / Q000378:metabolism; D003460:Crystallization; D008024:Ligands; D008958:Models, Molecular; D028223:Pinus / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D055314:Seed Storage Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D008024:Ligands; D055314:Seed Storage Proteins; D003300:Copper
keywords: 7S vicilin; X-ray crystallography; allergen; copper protein; pine nut