期刊
JOURNAL OF BIOLOGICAL CHEMISTRY
卷 281, 期 14, 页码 9471-9481出版社
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M512371200
关键词
-
Mutants with alteration to Asn(706) of the highly conserved (701)TGDGVND(707) motif in domain P of sarcoplasmic reticulum Ca2+-ATPase were analyzed for changes in transport cycle kinetics and binding of the inhibitors vanadate, BeF, AlF, and MgF. The fluorides likely mimic the phosphoryl group/P-i in the respective ground, transition, and product states of phosphoenzyme hydrolysis (Danko, S., Yamasaki, K., Daiho, T., and Suzuki, H. ( 2004) J. Biol. Chem. 279, 14991 - 14998). Binding of BeF, AlF, and MgF was also studied for mutant Glu(183) --> Ala, where the glutamate of the (181)TGES(184) motif in domain A is replaced. Mutations of Asn(706) and Glu(183) have in common that they dramatically impede the function of the enzyme in E2 states, but have little effect in E1. Contrary to the Glu(183) mutant, in which E2P slowly accumulates (Clausen, J. D., Vilsen, B., McIntosh, D. B., Einholm, A. P., and Andersen, J. P. (2004) Proc. Natl. Acad. Sci. U. S. A. 101, 2776 - 2781), E2P formation was not detectable with the Asn(706) mutants. Differential sensitivities of the mutants to inhibition by AlF, MgF, and BeF made it possible to distinguish different roles of Asn(706) and Glu(183). Hence, Asn(706) is less important than Glu(183) for gaining the transition state during E2P hydrolysis but plays critical roles in stabilization of E2P ground and E2 . P-i product states and in the major conformational changes associated with the Ca(2)E1P --> E2P and E2 --> Ca(2)E1 transitions, which seem to be facilitated by interaction of Asn(706) with domain A.
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。
推荐
暂无数据