4.4 Article

Structural and Biochemical Studies of a Fluoroacetyl-CoA-Specific Thioesterase Reveal a Molecular Basis for Fluorine Selectivity

期刊

BIOCHEMISTRY
卷 49, 期 43, 页码 9269-9279

出版社

AMER CHEMICAL SOC
DOI: 10.1021/bi101102u

关键词

-

资金

  1. University of California, Berkeley
  2. Arnold and Mabel Beckman Foundation
  3. National Science Foundation
  4. National Institutes of Health [1 T32 GMO66698]
  5. Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy [DE-AC02-05CH11231]

向作者/读者索取更多资源

We have initiated a broad-based program aimed at understanding the molecular basis of fluorine specificity in enzymatic systems, and in this context, we report crystallographic and biochemical studies on a fluoroacetyl-coenzyme A (CoA) specific thioesterase (FIK) from Streptomyces cattleya. Our data establish that FIK is competent to protect its host from fluoroacetate toxicity in vivo and demonstrate a 10(6)-fold discrimination between fluoroacetyl-CoA (k(cat)/K-m = 5 x 10(7) M-1 s(-1)) and acetyl-CoA (k(cat)/K-m = 30 M-1 s(-1)) based on a single fluorine substitution that originates from differences in both substrate reactivity and binding. We show that Thr 42, Glu 50, and His 76 are key catalytic residues and identify several factors that influence substrate selectivity. We propose that FIK minimizes interaction with the thioester carbonyl, leading to selection against acetyl-CoA binding that can be recovered in part by new C=O interactions in the T42S and T42C mutants. We hypothesize that the loss of these interactions is compensated by the entropic driving force for fluorinated substrate binding in a hydrophobic binding pocket created by a lid structure, containing Val 23, Leu 26, Phe 33, and Phe 36, that is not found in other structurally characterized members of this superfamily. We further suggest that water plays a critical role in fluorine specificity based on biochemical and structural studies focused on the unique Phe 36 gate residue, which functions to exclude water from the active site. Taken together, the findings from these studies offer molecular insights into organofluorine recognition and design of fluorine-specific enzymes.

作者

我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。

评论

主要评分

4.4
评分不足

次要评分

新颖性
-
重要性
-
科学严谨性
-
评价这篇论文

推荐

暂无数据
暂无数据