Spin equilibrium and O₂-binding kinetics of Mycobacterium tuberculosis CYP51 with mutations in the histidine-threonine dyad.

ABSTRACT: The acidic residues of the "acid-alcohol pair" in CYP51 enzymes are uniformly replaced with histidine. Herein, we adopt the Mycobacterium tuberculosis (mt) enzyme as a model system to investigate these residues' roles in finely tuning the heme conformation, iron spin state, and formation and decay of the oxyferrous enzyme. Properties of the mtCYP51 and the T260A, T260V, and H259A mutants were interrogated using UV-Vis and resonance Raman spectroscopies. Evidence supports that these mutations induce comprehensive changes in the heme environment. The heme iron spin states are differentially sensitive to the binding of the substrate, dihydrolanosterol (DHL). DHL and clotrimazole perturb the local environments of the heme vinyl and propionate substituents. Molecular dynamics (MD) simulations o

SUBMITTER: Jennings GK 

PROVIDER: S-EPMC4085784 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature