Yamamoto T, Nakashizuka M, Terada I
Sea Water Science Research Laboratory, Japan Tobacco Inc., Odawara, Kanagawa.
J Biochem. 1998 Jan;123(1):94-100. doi: 10.1093/oxfordjournals.jbchem.a021921.
Sialyltransferase 0160, a bacterial sialyltransferase which catalyzes the incorporation of NeuAc from CMP-NeuAc into the galactose residue of the carbohydrate chain at position 6, is produced by Photobacterium damsela JT0160. The gene coding for sialyltransferase 0160 (bst) was cloned, sequenced, and expressed in Escherichia coli. The sialyltransferase 0160 gene contains an open reading frame of 2,028 base pairs encoding a protein of 675 amino acid residues. The deduced amino acid sequence of sialyltransferase 0160 did not contain the sialylmotif and had no significant similarity to mammalian sialyltransferases. Crude extracts of cultured E. coli MV1184 cells carrying an expression plasmid for the sialyltransferase 0160 gene showed sialyltransferase activity, which was identified as beta-galactoside alpha2,6-sialyltransferase activity by enzymatic reaction product analysis. In addition, when mutant genes, lacking 3'-coding regions for COOH-terminal portions of the protein, which are thought to form alpha-helix structures, were expressed in E. coli MV1184, soluble-form enzymes were obtained. This implies that the COOH-terminal portion of sialyltransferase 0160 is required for membrane binding.
唾液酸转移酶0160是一种细菌唾液酸转移酶，可催化CMP - NeuAc中的NeuAc掺入到碳水化合物链6位的半乳糖残基中，由美人鱼发光杆菌JT0160产生。编码唾液酸转移酶0160（bst）的基因被克隆、测序并在大肠杆菌中表达。唾液酸转移酶0160基因包含一个2028个碱基对的开放阅读框，编码一个675个氨基酸残基的蛋白质。推导的唾液酸转移酶0160氨基酸序列不包含唾液酸基序，与哺乳动物唾液酸转移酶没有显著相似性。携带唾液酸转移酶0160基因表达质粒的培养大肠杆菌MV1184细胞的粗提物显示出唾液酸转移酶活性，通过酶促反应产物分析确定其为β-半乳糖苷α2,6-唾液酸转移酶活性。此外，当在大肠杆菌MV1184中表达缺失蛋白质COOH末端部分3'编码区（被认为形成α-螺旋结构）的突变基因时，获得了可溶性形式的酶。这意味着唾液酸转移酶0160的COOH末端部分对于膜结合是必需的。
