STRUCTURAL-ANALYSIS OF THE L-METHIONINE GAMMA-LYASE GENE FROM PSEUDOMONAS-PUTIDA
STRUCTURAL-ANALYSIS OF THE L-METHIONINE GAMMA-LYASE GENE FROM PSEUDOMONAS-PUTIDA
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DOI：
10.1093/oxfordjournals.jbchem.a124816
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发表时间：
1995-05-01
影响因子：
2.7
通讯作者：
TANAKA, H
中科院分区：
文献类型：
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作者：
INOUE, H;INAGAKI, K;TANAKA, H
克隆了恶臭假单胞菌L-蛋氨酸γ-裂解酶的基因，并从其核苷酸序列推导了该酶的一级结构，L-蛋氨酸γ-裂解酶基因在大肠杆菌中表达，BrCN消化肽的氨基酸序列与基因结构确定的L-蛋氨酸γ-裂解酶序列的相应部分一致，该多肽由398个氨基酸残基组成，计算分子量42,626，对应于同源四聚体酶的亚基，L-甲硫氨酸γ-裂解酶的推导氨基酸序列仅与其他众所周知的α，γ-消除和/或γ-取代吡哆醛5'-磷酸依赖性酶，例如胱硫醚γ-裂解酶、胱硫醚γ-合酶和O-乙酰高丝氨酸O-乙酰丝氨酸表现出广泛的同源性然而，推导的L-蛋氨酸γ-裂解酶的必需半胱氨酸残基在这些酶中并不保守，我们证实了L-蛋氨酸γ-裂解酶基因的3'侧翼区存在部分开放阅读框，其与大肠杆菌丙酮酸脱氢酶（硫辛酸酰胺）的N端区域表现出高度同源性，表明它与 L-蛋氨酸 γ-裂合酶一起参与 L-蛋氨酸的降解途径。
The gene encoding L-methionine gamma-lyase from Pseudomonas putida was cloned and the primary structure of the enzyme was deduced from its nucleotide sequence, The L-methionine gamma-lyase gene was expressed in Escherichia coli, The amino acid sequences of BrCN-digested peptides agreed with the corresponding parts of the L-methionine gamma-lyase sequence determined from the gene structure, The polypeptide is composed of 398 amino acid residues with a calculated molecular weight of 42,626, corresponding to the subunit of the homotetrameric enzyme, The deduced amino acid sequence of L-methionine gamma-lyase only showed extensive homology with other well known alpha,gamma-elimination and/or gamma-replacement pyridoxal 5'-phosphate-dependent enzymes, such as cystathionine gamma-lyase, cystathionine gamma-synthase, and O-acetylhomoserine O-acetylserine sulfhydrylase, that participate in the biosynthesis of sulfur amino acids, However, the deduced essential cysteine residue of L-methionine gamma-lyase was not conserved in these enzymes, We confirmed the presence of a part of an open reading frame in the 3'-flanking region of the L-methionine gamma-lyase gene, which showed high homology with the N-terminal region of pyruvate dehydrogenase (lipoamide) from E. coli, suggesting that it participates in the degradative pathway for L-methionine together with L-methionine gamma-lyase.