Direct FeS cluster involvement in generation of a radical in lysine 2,3-aminomutase
Direct FeS cluster involvement in generation of a radical in lysine 2,3-aminomutase
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DOI：
10.1021/bi0022184
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发表时间：
2000-12-26
期刊：
影响因子：
2.9
通讯作者：
Scott, RA
中科院分区：
文献类型：
--
作者：
Cosper, NJ;Booker, SJ;Scott, RA
赖氨酸 2,3-氨基变位酶 (KAM) 属于一类使用 FeS 簇和 S-腺苷-L-甲硫氨酸启动自由基依赖性化学反应的酶。在硒代蛋氨酸或硒-腺苷-L-硒代蛋氨酸存在下，对处于不同催化阶段的 KAM 进行硒 K 边 X 射线吸收光谱分析，结果表明，只有在连二亚硫酸盐和底物类似物反式-4,5-脱氢赖氨酸存在下，辅助因子才会被裂解。在 2.7 埃处出现了一个新的傅里叶变换峰，被指定为 Se-Fe 相互作用，与该裂解同时出现。这是首次证明 S-腺苷-L-甲硫氨酸或其裂解产物与此类酶中的 FeS 簇直接相互作用。
Lysine 2,3-aminomutase (KAM) belongs to a class of enzymes that use FeS clusters and S-adenosyl-L-methionine to initiate radical-dependent chemistry. Selenium K-edge X-ray absorption spectroscopic analysis of KAM poised at various stages of catalysis, in the presence of selenomethionine or Se-adenosyl-L-selenomethionine, reveals that the cofactor is cleaved only in the presence of dithionite and the substrate analogue trans-4,5-dehydrolysine. A new Fourier transform peak at 2.7 Angstrom, assigned as a Se-Fe interaction, appears concomitant with this cleavage. This is the first demonstration of a direct interaction of S-adenosyl-L-methionine, or its cleavage products, with the FeS cluster in this class of enzymes.