Catalytic specificity of the Lactobacillus plantarum cystathionine γ-lyase presumed by the crystallographic analysis
Catalytic specificity of the Lactobacillus plantarum cystathionine γ-lyase presumed by the crystallographic analysis
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DOI：
10.1038/s41598-020-71756-7
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发表时间：
2020-09-10
影响因子：
4.6
通讯作者：
Sugiyama, Masanori
中科院分区：
文献类型：
--
作者：
Matoba, Yasuyuki;Noda, Masafumi;Sugiyama, Masanori
由胱硫醚β-合酶（CBS）和胱硫醚γ-裂解酶（CGL）组成的反转硫途径在利用L-丝氨酸和L-蛋氨酸中的硫原子合成L-半胱氨酸中起作用。先前已经发现植物来源的乳酸菌植物乳杆菌（Lactobacillus plantarum）SN 35 N具有编码CBS样酶和CGL样酶的基因簇。此外，还证明了L. plantarum CBS可以从O-乙酰-L-丝氨酸和L-同型半胱氨酸合成胱硫醚。本研究的目的是表征L.植物我们已经发现，该酶对胱硫醚具有高γ-裂解酶活性以生成L-半胱氨酸，同时对L-胱氨酸具有β-裂解酶活性以生成L-半胱氨酸过硫化物。通过对失活的CGL K194 A突变体与硫胱苷肽复合物的晶体学分析，我们发现了识别硫胱苷肽或L-胱氨酸的远端氨基和羧基的残基。在活性位点处的PLP结合底物可以采取用于γ-或β-消除反应的结合姿势，其中前者是胱硫醚的情况下的主要反应。
The reverse transsulfuration pathway, which is composed of cystathionine beta-synthase (CBS) and cystathionine gamma-lyase (CGL), plays a role to synthesize l-cysteine using l-serine and the sulfur atom in l-methionine. A plant-derived lactic acid bacterium Lactobacillus plantarum SN35N has been previously found to harbor the gene cluster encoding the CBS- and CGL-like enzymes. In addition, it has been demonstrated that the L. plantarum CBS can synthesize cystathionine from O-acetyl-l-serine and l-homocysteine. The aim of this study is to characterize the enzymatic functions of the L. plantarum CGL. We have found that the enzyme has the high gamma-lyase activity toward cystathionine to generate l-cysteine, together with the beta-lyase activity toward l-cystine to generate l-cysteine persulfide. By the crystallographic analysis of the inactive CGL K194A mutant complexed with cystathionine, we have found the residues which recognize the distal amino and carboxyl groups of cystathionine or l-cystine. The PLP-bound substrates at the active site may take either the binding pose for the gamma- or beta-elimination reaction, with the former being the major reaction in the case of cystathionine.