Department of Chemistry and Biochemistry, Clemens-Schöpf-Institute, Technical University Darmstadt, Alarich-Weiss-Straße 4, 64287, Darmstadt, Germany.
Department of Microbiology and Biotechnology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany.
Chembiochem. 2022 Oct 6;23(19):e202200312. doi: 10.1002/cbic.202200312. Epub 2022 Sep 6.
γ-Glutamylamine synthetases are an important class of enzymes that play a key role in glutamate-based metabolism. Methionine sulfoximine (MSO) is a well-established inhibitor for the archetypal glutamine synthetase (GS) but inhibitors for most GS-like enzymes are unknown. Assuming a conserved catalytic mechanism for GS and GS-like enzymes, we explored if subtype-selective inhibitors can be obtained by merging MSO with the cognate substrates of the respective GS-like enzymes. Using GlnA4 from Streptomyces coelicolor, an enzyme recently shown to produce γ-glutamylethanolamine, we demonstrate that MSO can be reengineered in a straightforward fashion into potent and selective GlnA4 inhibitors. Linkage chemistry as well as linker length between the MSO moiety and the terminal hydroxyl group derived from ethanolamine were in agreement with the postulated phosphorylated catalytic intermediate. The best GlnA4 inhibitor 7 b potently blocked S. coelicolor growth in the presence of ethanolamine as the sole nitrogen source. Our results provide the first GlnA4 -specific inhibitors and suggest a general strategy to develop mechanism-based inhibitors for GS-like enzymes.
γ-谷氨酰胺合成酶是一类重要的酶，在谷氨酸代谢中起着关键作用。甲硫氨酸亚砜（MSO）是典型谷氨酰胺合成酶（GS）的一种成熟抑制剂，但大多数 GS 样酶的抑制剂尚不清楚。假设 GS 和 GS 样酶具有保守的催化机制，我们探索了是否可以通过将 MSO 与各自 GS 样酶的同源底物融合来获得亚型选择性抑制剂。我们使用来自链霉菌的 GlnA4，一种最近被证明能产生γ-谷氨酰乙醇胺的酶，证明了 MSO 可以以简单的方式重新设计成有效的、选择性的 GlnA4 抑制剂。连接化学以及 MSO 部分和乙醇胺衍生的末端羟基之间的连接子长度与假定的磷酸化催化中间物一致。最好的 GlnA4 抑制剂 7b 在乙醇胺作为唯一氮源存在的情况下，能有效地阻断链霉菌的生长。我们的结果提供了第一个 GlnA4 特异性抑制剂，并提出了一种开发 GS 样酶的基于机制的抑制剂的一般策略。
