BINDING-SPECIFICITY OF THE PERIPLASMIC OLIGOPEPTIDE-BINDING PROTEIN FROM ESCHERICHIA-COLI
BINDING-SPECIFICITY OF THE PERIPLASMIC OLIGOPEPTIDE-BINDING PROTEIN FROM ESCHERICHIA-COLI
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DOI：
10.1128/jb.168.2.775-779.1986
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发表时间：
1986-11-01
影响因子：
3.2
通讯作者：
STAROS, JV
中科院分区：
文献类型：
--
作者：
GUYER, CA;MORGAN, DG;STAROS, JV
肽底物与参与寡肽转运的大肠杆菌周质蛋白的结合所需的结构特性进行了调查，通过测量不同的肽的能力，以竞争结合在平衡透析测定与三肽Ala-Phe-[3 H]Gly。该蛋白特异性结合寡肽，而不能结合氨基酸或二肽。乙酰化的肽氨基末端的（Ala）3严重受损的结合，而酯化的羧基末端显着减少，但没有完全消除结合。由L-氨基酸组成的肽比含有D-残基或甘氨酸的肽更有效地竞争。一系列丙氨酰肽同系物的实验表明，随着链长超过三肽，竞争能力降低。与三肽同源物的竞争研究表明，各种各样的氨基酰基侧链的周质蛋白的耐受性，但侧链的组合物没有影响绑定。荧光发射数据表明，这种周质蛋白具有一个以上的基板结合位点能够区分肽的基础上的氨基酰基侧链。
The structural properties required for the binding of peptide substrates to the Escherichia coli periplasmic protein involved in oligopeptide transport were surveyed by measuring the ability of different peptides to compete for binding in an equilibrium dialysis assay with the tripeptide Ala-Phe-[3H]Gly. The protein specifically bound oligopeptides and failed to bind amino acids or dipeptides. Acetylation of the peptide amino terminus of (Ala)3 severely impaired binding, whereas esterification of the carboxyl terminus significantly reduced but did not completely eliminate binding. Peptides composed of L-amino acids competed more effectively than did peptides containing D-residues or glycine. Experiments with a series of alanyl peptide homologs demonstrated a decrease in competitive ability with increasing chain length beyond tripeptide. Competition studies with tripeptide homologs indicated that a wide variety of amino acyl side chains were tolerated by the periplasmic protein, but side-chain composition did effect binding. Fluorescence emission data suggested that this periplasmic protein possesses more than one substrate-binding site capable of distinguishing peptides on the basis of amino acyl side chains.