2012
A Single Mutation in a Tunnel to the Active Site Changes the Mechanism and Kinetics of Product Release in Haloalkane Dehalogenase LinB
BIEDERMANNOVÁ, Lada, Zbyněk PROKOP, Artur Wiktor GORA, Eva CHOVANCOVÁ, Mihály KOVÁCS et. al.Základní údaje
Originální název
A Single Mutation in a Tunnel to the Active Site Changes the Mechanism and Kinetics of Product Release in Haloalkane Dehalogenase LinB
Autoři
BIEDERMANNOVÁ, Lada (203 Česká republika), Zbyněk PROKOP (203 Česká republika, domácí), Artur Wiktor GORA (616 Polsko, domácí), Eva CHOVANCOVÁ (203 Česká republika, domácí), Mihály KOVÁCS (348 Maďarsko), Jiří DAMBORSKÝ (203 Česká republika, garant, domácí) a Rebecca C. WADE (276 Německo)
Vydání
The Journal of Biological Chemistry, USA, 2012, 0021-9258
Další údaje
Jazyk
angličtina
Typ výsledku
Článek v odborném periodiku
Obor
Genetika a molekulární biologie
Stát vydavatele
Spojené státy
Utajení
není předmětem státního či obchodního tajemství
Impakt faktor
Impact factor: 4.651
Kód RIV
RIV/00216224:14310/12:00057142
Organizační jednotka
Přírodovědecká fakulta
UT WoS
000308074600073
Klíčová slova anglicky
HLD; haloalkane dehalogenase; MD; molecular dynamics; RAMD; random acceleration molecular dynamics; ABF; adaptive biasing force; RC; reaction coordinate; FEP; free energy perturbation; NATA; N-acetyltryptophan amide
Změněno: 22. 4. 2013 15:09, Ing. Andrea Mikešková
Anotace
V originále
Many enzymes have buried active sites. The properties of the tunnels connecting the active site with bulk solvent affect ligand binding and unbinding and also the catalytic properties. Here, we investigate ligand passage in the haloalkane dehalogenase enzyme LinB and the effect of replacing leucine by a bulky tryptophan at a tunnel-lining position. Transient kinetic experiments show that the mutation significantly slows down the rate of product release. Moreover, the mechanism of bromide ion release is changed from a one-step process in the wild type enzyme to a two-step process in the mutant. The rate constant of bromide ion release corresponds to the overall steady-state turnover rate constant, suggesting that product release became the rate-limiting step of catalysis in the mutant. We explain the experimental findings by investigating the molecular details of the process computationally. Analysis of trajectories from molecular dynamics simulations with a tunnel detection software reveals differences in the tunnels available for ligand egress. Corresponding differences are seen in simulations of product egress using a specialized enhanced sampling technique. The differences in the free energy barriers for egress of a bromide ion obtained using potential of mean force calculations are in good agreement with the differences in rates obtained from the transient kinetic experiments. Interactions of the bromide ion with the introduced tryptophan are shown to affect the free energy barrier for its passage. The study demonstrates how the mechanism of an enzymatic catalytic cycle and reaction kinetics can be engineered by modification of protein tunnels.
Návaznosti
ED0001/01/01, projekt VaV |
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IAA401630901, projekt VaV |
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