的2.3 a分辨率结构麦芽糖或maltodextrin-binding蛋白质、细菌的主动运输的主要受体和趋化性。
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Spurlino JC,路GY, Quiocho足总
的2.3 a分辨率结构麦芽糖或maltodextrin-binding蛋白质、细菌的主动运输的主要受体和趋化性。
J生物化学杂志。1991年3月15日,266(8):5202 - 19所示。
- PubMed ID
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2002054 (在PubMed]
- 文摘
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麦芽糖或maltodextrin-binding蛋白质的三维结构(= 40622)先生与绑定麦芽糖得到晶体分析2.8 a分辨率。结构,在2.3部分精制,椭圆形的总体尺寸30 x 40 x 65分为两个截然不同的球状域由一个深沟。虽然每个域是由两个肽段的氨基和羧基末端部分,这两个领域表现出类似supersecondary结构,组成的一个中央beta-pleated板两侧有两三个平行的阿尔法螺旋。槽,深度18和基地约9 x 18,包含maltodextrin-binding网站。我们曾观察到相同的一般特征well-refined其他六周质的结构与特异性受体L-arabinose, D-galactose /葡萄糖、硫酸盐、磷酸盐、亮氨酸、异亮氨酸、缬氨酸、亮氨酸。绑定麦芽糖埋在槽和几乎完全无法访问大部分溶剂。槽是人口稠密的极地和芳香组其中许多参与广泛的氢键和范德华相互作用和麦芽糖。所有的二糖羟基,形成一个外围极地表面大约在平面上的糖环,绑在总共11直接氢键6侧链,一个Trp侧链,和一个肽骨干NH,和五个间接通过水分子氢键。麦芽糖是四芳香族侧链之间。这些芳香残留的结果叠加glucosyl单位提供了大部分的范德华接触的复杂。 The nonreducing glucosyl unit of the maltose is involved in approximately twice as many hydrogen bonds and van der Waals contacts as the glucosyl unit at the reducing end. The binding protein-maltose complex shows the best example of the extensive use of polar and aromatic residues in binding oligosaccharides. The tertiary structure of the maltodextrin-binding protein, along with the results of genetic studies by a number of investigators, has also enabled us for the first time to map the different regions on the surface of the protein involved in the interactions with the membrane-bound protein components necessary for transport of and chemotaxis toward maltodextrins. These sites permit distinction of the "open cleft" (without bound sugar) and closed (with bound sugar) conformations of the binding protein by the chemotactic signal transducer with which the maltodextrin-binding protein interacts.(ABSTRACT TRUNCATED AT 250 WORDS)