meso-diaminopimelic酸脱氢酶的三维结构棒状杆菌glutamicum。
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Scapin G, Reddy SG,布兰查德JS
meso-diaminopimelic酸脱氢酶的三维结构棒状杆菌glutamicum。
生物化学。1996年10月22日,35 (42):13540 - 51。
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8885833 (在PubMed]
- 文摘
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Diaminopimelate脱氢酶催化的NADPH-dependent减少氨和L-2-amino-6-ketopimelate形成meso-diaminopimelate,赖氨酸在细菌的直接前体赖氨酸生物合成途径。因为哺乳动物缺乏这种代谢途径抑制剂的酶这一途径可能是有用的作为抗生素或除草剂。Diaminopimelate脱氢酶催化D的只有氧化脱氨基作用的一种氨基酸配置和另外必须区分两个手性氨基酸中心在同一对称的衬底。的棒状杆菌glutamicum酶被克隆,在大肠杆菌中表达,纯化,同质性(Reddy, s G使用标准的生化过程。Scapin, G。&布兰查德,j . s .(1996):蛋白质结构、功能。麝猫。25日,514 - 516]。二进制的复杂的三维结构diaminopimelate脱氢酶与辅酶ii +已经解决了使用多个同形替代过程和noncrystallographic对称平均。由此产生的模型提炼对传统晶体衍射数据2.2 r因子为17.0%。Diaminopimelate脱氢酶为结构不相同的子单元。每个单元由三个领域。 The N-terminal domain contains a modified dinucleotide binding domain, or Rossman fold (six central beta-strands in a 213456 topology surrounded by five alpha-helices). The second domain contains two alpha-helices and three beta-strands. This domain is referred to as the dimerization domain, since it is involved in forming the monomer--monomer interface of the dimer. The third or C-terminal domain is composed of six beta-strands and five alpha-helices. The relative position of the N- and C-terminal domain in the two monomers is different, defining an open and a closed conformation that may represent the enzyme's binding and active state, respectively. In both monomers the nucleotide is bound in an extended conformation across the C-terminal portion of the beta-sheet of the Rossman fold, with its C4 facing the C-terminal domain. In the closed conformer two molecules of acetate have been refined in this region, and we postulate that they define the DAP binding site. The structure of diaminopimelate dehydrogenase shows interesting similarities to the structure of glutamate dehydrogenase [Baker, P. J., Britton, K. L., Rice, D. W., Rob, A., & Stillmann, T.J. (1992a) J. Mol. Biol. 228, 662-671] and leucine dehydrogenase [Baker, P.J., Turnbull, A.P., Sedelnikova, S.E., Stillman, T. J., & Rice, D. W. (1995) Structure 3, 693-705] and also resembles the structure of dihydrodipicolinate reductase [Scapin, G., Blanchard, J. S., & Sacchettini, J. C. (1995) Biochemistry 34, 3502-3512], the enzyme immediately preceding it in the diaminopimelic acid/lysine biosynthetic pathway.