Vollenbroich D, Kluge B, D'Souza C, Zuber P, Vater J
Institut für Biochemie und Molekulare Biologie, Technische Universität Berlin, Germany.
FEBS Lett. 1993 Jul 5;325(3):220-4. doi: 10.1016/0014-5793(93)81077-d.
The reactive serine of the TGGHSL thioester binding motif of the first amino acid-activating domain of surfactin synthetase was replaced by alanine using site-directed mutagenesis. The multienzyme from cells of the resulting mutant lost its ability for thioester formation with L-Glu and was therefore inactive in surfactin production. The thiolation reactions catalyzed by the other amino acid-activating domains of surfactin synthetase were not affected by the mutation. The results show that L-Glu is activated at the first domain of surfactin synthetase, and give further evidence that a serine residue is essential for substrate amino acid activation at the reaction centers of peptide synthetases.
利用定点诱变技术，将表面活性素合成酶第一个氨基酸激活结构域的TGGHSL硫酯结合基序中的反应性丝氨酸替换为丙氨酸。所得突变体细胞中的多酶失去了与L-谷氨酸形成硫酯的能力，因此在表面活性素生产中无活性。表面活性素合成酶其他氨基酸激活结构域催化的硫醇化反应不受该突变影响。结果表明，L-谷氨酸在表面活性素合成酶的第一个结构域被激活，并进一步证明丝氨酸残基对于肽合成酶反应中心的底物氨基酸激活至关重要。
