2 angstrom resolution structure of DppA, a periplasmic dipeptide transport chemosensory receptor
2 angstrom resolution structure of DppA, a periplasmic dipeptide transport chemosensory receptor
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DOI：
10.1021/bi00051a006
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发表时间：
1995-12-26
期刊：
影响因子：
2.9
通讯作者：
Quiocho, FA
中科院分区：
文献类型：
--
作者：
Nickitenko, AV;Trakhanov, S;Quiocho, FA
约50种周质结合蛋白的家族，其表现出不同的特异性（例如，分子量范围为20 - 58 kDa，是研究原子水平结构和分子识别的金矿。这些蛋白质充当主动转运系统或渗透酶的初始受体。这些蛋白质中约有六种，包括二肽结合蛋白（DppA），也是趋化性的主要受体。DppA（M（r）= 57400）的未结合形式的结构已经被确定并被细化到0.169至2埃分辨率的R因子。DppA由两个不同的结构域（I和II）组成，所述结构域由两个“铰链"区段连接，所述”铰链“区段形成两个结构域之间的宽沟的基部的一部分。两个结构域的相对取向使蛋白质呈梨状，结构域I和结构域II分别形成较大和较小的顶端。从尖端到圆形底部测量约85埃，最宽直径约为60埃。结构域I由两个整合的亚结构域组成，从氨基末端和羧基末端的两个单独的多肽片段折叠而成。更紧凑的域II。由插入段形成。二肽结合蛋白结构与类似寡肽结合蛋白结合形式的结构的比较[驯服，J.R.H.，Murshudov，C.N.，Dodson，E.J.，尼尔，T.K.，Dodson，G. G.，希金斯，C.F.，和威尔金森，A. J.（1994）Science 264，1578-1581]揭示了区分两种蛋白质的配体特异性的主要特征，并描述了两个结构域之间的大铰链弯曲（约55度）。
The family of about 50 periplasmic binding proteins, which exhibit diverse specificity (e.g., carbohydrates, amino acids, dipeptides, oligopeptides, oxyanions, metals, and vitamins) and range in size from 20 to 58 kDa, is a gold mine for an atomic-level investigation of structure and molecular recognition. These proteins serve as initial receptors for active transport systems or permeases. About six of these proteins, including the dipeptide-binding protein (DppA), are also primary receptors for chemotaxis. The structure of the unbound form of DppA (M(r) = 57 400) has been determined and refined to an R-factor of 0.169 to 2 Angstrom resolution. DppA consists of two distinct domains (I and II) connected by two ''hinge'' segments which form part of the base of the wide groove between the two domains. The relative orientation of the two domains gives the protein a pearlike shape, with domain I and domain II forming the larger and smaller apical ends, respectively. From the tip to the rounded bottom measures about 85 Angstrom, and the widest diameter is about 60 Angstrom. Domain I, which consists of two integrated subdomains, is folded from two separate polypeptide segments from the amino- and carboxyl-terminal ends. The more compact domain II. is formed from the intervening segment. Comparison of the dipeptide-binding protein structure with that of the bound form of the similar oligopeptide-binding protein [Tame, J.R.H., Murshudov, C.N., Dodson, E.J., Neil, T.K., Dodson, G.G., Higgins, C.F., & Wilkinson, A.J. (1994) Science 264, 1578-1581] reveals the major features that differentiate the ligand specificity of the two proteins and describe the large hinge bending (about 55 degrees) between the two domains.