2ruq
From Proteopedia
solution structure of human Pin1 PPIase mutant C113A
Structural highlights
Function[PIN1_HUMAN] Essential PPIase that regulates mitosis presumably by interacting with NIMA and attenuating its mitosis-promoting activity. Displays a preference for an acidic residue N-terminal to the isomerized proline bond. Catalyzes pSer/Thr-Pro cis/trans isomerizations. Down-regulates kinase activity of BTK. Can transactivate multiple oncogenes and induce centrosome amplification, chromosome instability and cell transformation. Required for the efficient dephosphorylation and recycling of RAF1 after mitogen activation.[1] [2] [3] Publication Abstract from PubMedIntimate cooperativity among active site residues in enzymes is a key factor for regulating elaborate reactions that would otherwise not occur readily. Peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (Pin1) is the phosphorylation-dependent cis-trans peptidyl-prolyl isomerase (PPIase) that specifically targets phosphorylated Ser/Thr-Pro motifs. Residues C113, H59, H157, and T152 form a hydrogen bond network in the active site, as in the noted connection. Theoretical studies have shown that protonation to thiolate C113 leads to rearrangement of this hydrogen bond network, with switching of the tautomeric states of adjacent histidines (H59 and H157) [Barman, A., and Hamelberg, D. (2014) Biochemistry 53, 3839-3850]. This is called the "dual-histidine motif". Here, C113A and C113S Pin1 mutants were found to alter the protonation states of H59 according to the respective residue type replaced at C113, and the mutations resulted in disruption of the hydrogen bond within the dual-histidine motif. In the C113A mutant, H59 was observed to be in exchange between epsilon- and delta-tautomers, which widened the entrance of the active site cavity, as seen by an increase in the distance between residues A113 and S154. The C113S mutant caused H59 to exchange between the epsilon-tautomer and imidazolium while not changing the active site structure. Moreover, the imidazole ring orientations of H59 and H157 were changed in the C113S mutant. These results demonstrated that a mutation at C113 modulates the hydrogen bond network dynamics. Thus, C113 acts as a pivot to drive the concerted function among the residues in the hydrogen bond network, as theoretically predicted. Allosteric Breakage of the Hydrogen Bond within the Dual-Histidine Motif in the Active Site of Human Pin1 PPIase.,Wang J, Tochio N, Kawasaki R, Tamari Y, Xu N, Uewaki J, Utsunomiya-Tate N, Tate S Biochemistry. 2015 Aug 25;54(33):5242-53. doi: 10.1021/acs.biochem.5b00606. Epub , 2015 Aug 13. PMID:26226559[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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