State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.
World J Microbiol Biotechnol. 2013 Nov;29(11):2067-76. doi: 10.1007/s11274-013-1370-9. Epub 2013 Aug 3.
Pseudomonas plecoglossicida, a bacterium strain that exhibits high Serine hydroxymethyltransferase (SHMT) activity, was isolated from the seawater. A full-length glyA encoding SHMT was obtained by a modified thermal asymmetric interlaced-PCR (TRIL-PCR), which consisted of 1,254 bp, encoded a 417 amino acid polypeptide, and shared the highest identity (75 %) with a glyA gene from Acinetobacter radioresistens CMC-1. Recombinant glyA gene was expressed in Escherichia coli BL21 (DE3) and purified by electrophoretic homogeneity. The enzyme showed the optimal activity at pH 8.0 and 40 °C, and remained stable in high alkali conditions. Using SHMT to produce L-serine by catalyzing the reaction of glycine and tetrahydrofolate is one of the most promising routes to synthesize L-serine, achieving 33.4 mM L-serine at the 12th h of the enzymatic reaction with the substrates of glycine (133 mM) and formaldehyde (13.3 mM). The properties make the SHMT a candidate for further enzymatic studies and industrial applications.
从海水中分离到一株具有高丝氨酸羟甲基转移酶 (SHMT) 活性的假交替单胞菌。通过改良的热不对称交错 PCR (TRIL-PCR) 获得了全长的 glyA 编码 SHMT，该基因由 1254bp 组成，编码 417 个氨基酸的多肽，与耐辐射不动杆菌 CMC-1 的 glyA 基因具有最高的同源性 (75%)。重组 glyA 基因在大肠杆菌 BL21 (DE3) 中表达，并通过电泳纯度进行纯化。该酶在 pH8.0 和 40°C 下表现出最佳活性，并且在高碱性条件下保持稳定。利用 SHMT 催化甘氨酸和四氢叶酸的反应生产 L-丝氨酸是合成 L-丝氨酸最有前途的途径之一，在 123 mM 甘氨酸和 13.3 mM 甲醛作为底物的酶反应 12 小时后，可达到 33.4 mM 的 L-丝氨酸。这些特性使 SHMT 成为进一步酶学研究和工业应用的候选者。
