TY  - JOUR
A1  - Götze, Jan Philipp
A1  - Saalfrank, Peter
T1  - Quantum chemical modeling of the kinetic isotope effect of the carboxylation step in RuBisCO
JF  - Journal of molecular modeling
N2  - Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), the most important enzyme for the assimilation of carbon into biomass, features a well-known isotope effect with regards to the CO2 carbon atom. This kinetic isotope effect alpha = k (12)/k (13) for the carboxylation step of the RuBisCO reaction sequence, and its microscopic origin, was investigated with the help of cluster models and quantum chemical methods [B3LYP/6-31G(d,p)]. We use a recently proposed model for the RuBisCO active site, in which a water molecule remains close to the reaction center during carboxylation of ribulose-1,5-bisphosphate [B. Kannappan, J.E. Gready, J. Am. Chem. Soc. 130 (2008), 15063]. Alternative active-site models and/or computational approaches were also tested. An isotope effect alpha for carboxylation is found, which is reasonably close to the one measured for the overall reaction, and which originates from a simple frequency shift of the bending vibration of (CO2)-C-12 compared to (CO2)-C-13. The latter is the dominant mode for the product formation at the transition state.
KW  - Cluster model
KW  - Dark reactions
KW  - Densityfunctional theory
KW  - Isotope effect
KW  - Photosynthesis
KW  - Quantum chemistry
KW  - RuBisCO
Y1  - 2012
U6  - https://doi.org/10.1007/s00894-011-1207-0
SN  - 1610-2940
VL  - 18
IS  - 5
SP  - 1877
EP  - 1883
PB  - Springer
CY  - New York
ER  -