The legume symbiotic nitrogen-fixing bacterium, B. diazoefficiens strain USDA110, utilizes methanol for growth in the presence of light lanthanides, such as La3+, Ce3+, Pr3+ or Nd3+, and its cells possess significant methanol dehydrogenase (MDH) activity. We purified MDH to homogeneity from B. diazoefficiens strain USDA110 grown in a methanol/Ce3+ medium; the protein was identified as XoxF5-type MDH (blr6213). The purified XoxF contained 0.58 cerium atoms per enzyme subunit. Moreover, the in-solution structure of XoxF was analyzed by small angle X-ray scattering (SAXS) analysis; the radius of gyration (Rg) and maximum particle dimension (Dmax) of XoxF were calculated to be 32.3 and 96.8 Å, respectively, suggesting that XoxF adopts a dimer structure in solution. These results show that B. diazoefficiens strain USDA110 has XoxF, a lanthanides-dependent MDH, which has methanol oxidation activity and is induced by methanol/lanthanaides, and that lanthanide is one of the important factors in methanol utilization by the strain.

中文翻译：

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来自豆科植物共生固氮细菌 Bradyrhizobium diazoefficiens USDA110 的镧系元素依赖性甲醇脱氢酶

豆科植物共生固氮菌 B. diazoefficiens USDA110 利用甲醇在轻镧系元素（如 La3+、Ce3+、Pr3+ 或 Nd3+）存在下生长，其细胞具有显着的甲醇脱氢酶 (MDH) 活性。我们从在甲醇/Ce3+ 培养基中生长的重氮芽孢杆菌 USDA110 菌株中纯化 MDH 至同质性；该蛋白质被鉴定为 XoxF5 型 MDH (blr6213)。纯化的 XoxF 每个酶亚基含有 0.58 个铈原子。此外，通过小角X射线散射（SAXS）分析对XoxF的溶液结构进行了分析；XoxF 的回转半径 (Rg) 和最大颗粒尺寸 (Dmax) 分别计算为 32.3 和 96.8 Å，表明 XoxF 在溶液中采用二聚体结构。这些结果表明重氮芽孢杆菌菌株 USDA110 具有 XoxF，