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Computational Study of the Phosphoryl Transfer Catalyzed by a Cyclin‐Dependent Kinase
Author(s) -
De Vivo Marco,
Cavalli Andrea,
Carloni Paolo,
Recanatini Maurizio
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200700044
Subject(s) - chemistry , cyclin dependent kinase , serine , deprotonation , stereochemistry , density functional theory , threonine , residue (chemistry) , catalysis , kinase , cyclin dependent kinase 2 , phosphorylation , protein kinase a , computational chemistry , biochemistry , organic chemistry , ion , cell cycle , cell
A cyclin‐dependent kinase, Cdk2, catalyzes the transfer of the γ‐phosphate from ATP to a threonine or serine residue of its polypeptide substrates. Here, we investigate aspects of the reaction mechanism of Cdk2 by gas‐phase density functional calculations, classical molecular dynamics, and Car–Parrinello QM/MM simulations. We focus on the role of the conserved Asp127 and on the nature of the phosphoryl transfer reaction mechanism catalyzed by Cdk2. Our findings suggest that Asp127 is active in its deprotonated form by assisting the formation of the near‐attack orientation of the substrate serine or threonine. Therefore, the residue does not act as a general base during the catalysis. The mechanism for the phosphoryl transfer is a single S N 2‐like concerted step, which shows a phosphorane‐like transition state geometry. Although the resulting reaction mechanism is in agreement with a previous density functional study of the same catalytic reaction mechanism (Cavalli et al. , Chem. Comm. 2003 , 1308–1309), the reaction barrier is considerably lower when QM/MM calculations are performed, as in this study (≈42 kcal mol −1 QM vs. ≈24 kcal mol −1 QM/MM); this indicates that important roles for the catalysis are played by the protein environment and solvent waters. Because of the high amino acid sequence conservation among the whole family of cyclin‐dependent kinases (CDKs), these results could be general for the CDK family.