Tame J R, Murshudov G N, Dodson E J, Neil T K, Dodson G G, Higgins C F, Wilkinson A J
Department of Chemistry, University of York, UK.
Science. 1994 Jun 10;264(5165):1578-81. doi: 10.1126/science.8202710.
Specific protein-ligand interactions are critical for cellular function, and most proteins select their partners with sharp discrimination. However, the oligopeptide-binding protein of Salmonella typhimurium (OppA) binds peptides of two to five amino acid residues without regard to sequence. The crystal structure of OppA reveals a three-domain organization, unlike other periplasmic binding proteins. In OppA-peptide complexes, the ligands are completely enclosed in the protein interior, a mode of binding that normally imposes tight specificity. The protein fulfills the hydrogen bonding and electrostatic potential of the ligand main chain and accommodates the peptide side chains in voluminous hydrated cavities.
特定的蛋白质-配体相互作用对细胞功能至关重要，大多数蛋白质会严格筛选其伴侣。然而，鼠伤寒沙门氏菌的寡肽结合蛋白（OppA）能结合两到五个氨基酸残基的肽段，而不考虑序列。OppA的晶体结构显示出一种三结构域组织，这与其他周质结合蛋白不同。在OppA-肽复合物中，配体完全被包裹在蛋白质内部，这种结合模式通常会带来严格的特异性。该蛋白质满足配体主链的氢键和静电势，并在大量的水合腔中容纳肽侧链。
