E275 and F276 in beta12-beta13 loop of protein phosphatase-1 resist Mn2+-mediated activation.
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.
Xie
Xiujie
X
Department of Biochemistry and Molecular Biology, Beijing Normal University, Beijing Key Laboratory, Beijing, 100875, P.R. China.
Huang
Wei
W
Xue
Chengzhe
C
Wei
Qun
Q
D004789:Enzyme Activation / Q000187:drug effects; D007700:Kinetics; D008345:Manganese / Q000494:pharmacology*; D011487:Protein Conformation / Q000187:drug effects; D054645:Protein Phosphatase 1 / Q000032:analysis / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017384:Sequence Deletion
D008345:Manganese; D054645:Protein Phosphatase 1