Stim-Herndon K P, Petersen D J, Bennett G N
Department of Biochemistry and Cell Biology-MS140, Rice University, Houston, TX 77005-1892.
Gene. 1995 Feb 27;154(1):81-5. doi: 10.1016/0378-1119(94)00838-j.
Thiolase (Thl) is an important enzyme at the junction in the pathway leading to the production of either acids (acetate or butyrate) or solvents (acetone, butanol or ethanol) during the growth of Clostridium acetobutylicum ATCC 824. Cloning and expression of the Thl-encoding gene (thl) has been described [Petersen and Bennett, Appl. Environ. Microbiol. 57 (1991) 2735-2741], as has the purification and properties of the enzyme [Wiesenborn et al., Appl. Environ. Microbiol. 54 (1988) 2717-2722]. Here, we present the complete nucleotide sequence (1.9 kb) of thl. The gene encodes a protein of 392 amino acids (aa) (41,237 Da), which mass is in agreement with previous findings using the purified protein. Primer extension analysis has defined the promoter region, and a stem-loop structure found at the end of thl indicates that it is not part of an operon. The aa sequence of Thl showed homology to those of four other beta-ketothiolases: (i) PhbC of Alcaligenes eutrophus, (ii) PhbA of Chromatium vinosum, (iii) PhbA of Thiocystis violacea and (iv) PhbA of Zoogloea ramigera. The C terminus of an open reading frame found upstream from the Thl sequence is similar to OrfX of Bacillus subtilis and to NfrC of Escherichia coli.
硫解酶（Thl）是丙酮丁醇梭菌ATCC 824生长过程中，在通向产生酸（乙酸或丁酸）或溶剂（丙酮、丁醇或乙醇）的途径交汇处的一种重要酶。硫解酶编码基因（thl）的克隆和表达已有报道[彼得森和贝内特，《应用与环境微生物学》57（1991）2735 - 2741]，该酶的纯化及性质也已有报道[维森伯恩等人，《应用与环境微生物学》54（1988）2717 - 2722]。在此，我们展示thl的完整核苷酸序列（1.9 kb）。该基因编码一个由392个氨基酸（aa）组成的蛋白质（41,237 Da），其质量与先前使用纯化蛋白的研究结果一致。引物延伸分析确定了启动子区域，在thl末端发现的一个茎环结构表明它不是操纵子的一部分。硫解酶的氨基酸序列与其他四种β - 酮硫解酶的序列具有同源性：（i）嗜糖产碱菌的PhbC，（ii）嗜硫红假单胞菌的PhbA，（iii）紫色硫囊菌的PhbA，以及（iv）生枝动胶菌的PhbA。在硫解酶序列上游发现的一个开放阅读框的C末端与枯草芽孢杆菌的OrfX和大肠杆菌的NfrC相似。
