DFT calculations of comparative energetics and ENDOR/Mossbauer properties for two protonation states of the iron dimer cluster of ribonucleotide reductase intermediate X.

ABSTRACT: Two models (I and II) for the active site structure of class-I ribonucleotide reductase (RNR) intermediate X in subunit R2 have been studied in this paper, using broken-symmetry density functional theory (DFT) incorporated with the conductor like screening (COSMO) solvation model and with the finite-difference Poisson-Boltzmann self-consistent reaction field (PB-SCRF) calculations. Only one of the bridging groups between the two iron centers is different between model-I and model-II. Model-I contains two mu-oxo bridges, while model-II has one bridging oxo and one bridging hydroxo. These are large active site models including up to the fourth coordination shell H-bonding residues. Mössbauer and ENDOR hyperfine property calculations show that model-I is more likely to represent the active si

SUBMITTER: Han WG 

PROVIDER: S-EPMC2746754 | biostudies-literature | 2009 Aug

REPOSITORIES: biostudies-literature