Dickschat Jeroen S, Rinkel Jan, Klapschinski Tim, Petersen Jörn
Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Strasse 1, 53121, Bonn, Germany.
Leibniz-Institut DSMZ, Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Inhoffenstrasse 7b, 38124, Braunschweig, Germany.
Chembiochem. 2017 Nov 16;18(22):2260-2267. doi: 10.1002/cbic.201700358. Epub 2017 Oct 20.
The l-cystine β-lyase from Phaeobacter inhibens is involved in the biosynthesis of the sulfur-containing antibiotic tropodithietic acid. The recombinant enzyme was obtained by heterologous expression in Escherichia coli and biochemically characterised by unambiguous chemical identification of the products formed from the substrate l-cystine, investigation of the substrate spectrum, determination of the enzyme kinetics, sequence alignment with closely related homologues and site-directed mutagenesis to identify a highly conserved lysine residue that is critical for functionality. PatB from P. inhibens is a new member of the small group of characterised l-cystine β-lyases and the first example of an enzyme with such an activity that is required for the biosynthesis of an antibiotic. A comparison of PatB to previously reported enzymes with l-cystine β-lyase activity from bacteria and plants is given.
来自抑制嗜盐菌（Phaeobacter inhibens）的L-胱氨酸β-裂合酶参与含硫抗生素2,4,6-三甲基-5-丙基-4H-噻吩并[3,2-b]噻吩-2-羧酸（tropodithietic acid）的生物合成。通过在大肠杆菌中进行异源表达获得了重组酶，并对其进行了生化特性鉴定，包括对由底物L-胱氨酸形成的产物进行明确的化学鉴定、研究底物谱、测定酶动力学、与密切相关的同源物进行序列比对以及进行定点诱变以鉴定对功能至关重要的高度保守赖氨酸残基。抑制嗜盐菌的PatB是已鉴定的L-胱氨酸β-裂合酶小群体中的新成员，也是抗生素生物合成所需的具有这种活性的酶的首个实例。给出了PatB与先前报道的具有来自细菌和植物的L-胱氨酸β-裂合酶活性的酶的比较。
