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Published on: May 26, 2017
E275 and F276 in beta12-beta13 loop of protein phosphatase-1 resist Mn2+-mediated activation
Xiujie Xie1, Wei Huang, Chengzhe Xue
1Department of Biochemistry and Molecular Biology, Beijing Normal University, Beijing Key Laboratory, Beijing, 100875, P.R. China.
Abstract:
Protein phosphatase-1 (PP1) is one of the most important Ser/Thr phosphatases in eukaryotic cells. G274, E275, and F276 are located at the tip of the beta12-beta13 loop of protein phosphatase-1. Without Mn2+, the basal activities and intrinsic fluorescence spectra of all single and double deletion mutants of G274, E275, and F276 were similar to those of PP1, but deletion mutants DeltaE275 and DeltaE275F276 showed hyperactivity and corresponding changes in intrinsic fluorescence spectra when Mn2+ was present. This suggests that the conformation transition resulting from the combined effect of mutation and Mn2+ accounts for the hyperactivity of mutants. These observations imply that E275 and F276 play a role in resisting enzyme activation by Mn2+ in PP1.
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