Zhang Yanfeng, Gao Xiaoli
Genetics Graduate Program, Michigan State University, East Lansing, MI 48824, USA.
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2012 Jan 1;68(Pt 1):63-5. doi: 10.1107/S1744309111048111. Epub 2011 Dec 24.
L-Lactate dehydrogenase (LDH) is an important enzyme involved in the last step of glycolysis that catalyzes the reversible conversion of pyruvate to L-lactate with the simultaneous oxidation of NADH to NAD(+). In this study, wild-type LDH from Bacillus subtilis (BsLDH-WT) and the H171C mutant (BsLDH-H171C) were expressed in Escherichia coli and purified to near-homogeneity. BsLDH-WT was crystallized in the presence of fructose 1,6-bisphosphate (FBP) and NAD(+) and the crystal diffracted to 2.38 Å resolution. The crystal belonged to space group P3, with unit-cell parameters a = b = 171.04, c = 96.27 Å. BsLDH-H171C was also crystallized as the apoenzyme and in complex with NAD(+), and data sets were collected to 2.20 and 2.49 Å resolution, respectively. Both BsLDH-H171C crystals belonged to space group P3, with unit-cell parameters a = b = 133.41, c = 99.34 Å and a = b = 133.43, c = 99.09 Å, respectively. Tetramers were observed in the asymmetric units of all three crystals.
L-乳酸脱氢酶（LDH）是参与糖酵解最后一步的一种重要酶，它催化丙酮酸可逆转化为L-乳酸，同时将NADH氧化为NAD(+)。在本研究中，枯草芽孢杆菌野生型LDH（BsLDH-WT）和H171C突变体（BsLDH-H171C）在大肠杆菌中表达并纯化至接近均一性。BsLDH-WT在1,6-二磷酸果糖（FBP）和NAD(+)存在下结晶，晶体衍射分辨率达到2.38 Å。该晶体属于P3空间群，晶胞参数a = b = 171.04，c = 96.27 Å。BsLDH-H171C也以脱辅酶形式以及与NAD(+)形成的复合物形式结晶，分别收集到分辨率为2.20 Å和2.49 Å的数据集。两种BsLDH-H171C晶体均属于P3空间群，晶胞参数分别为a = b = 133.41，c = 99.34 Å和a = b = 133.43，c = 99.09 Å。在所有三种晶体的不对称单元中均观察到四聚体。
