Binding of O2 and NO to heme in heme-nitric oxide/oxygen-binding (H-NOX) proteins. A theoretical study.

ABSTRACT: The binding of O2 and NO to heme in heme-nitric oxide/oxygen-binding (H-NOX) proteins has been investigated with DFT as well as dispersion-corrected DFT methods. The local protein environment was accounted for by including the six nearest surrounding residues in the studied systems. Attention was also paid to the effects of the protein environment, particularly the distal Tyr140, on the proximal iron-histidine (Fe-His) binding. The Heme-AB (AB = O2, NO) and Fe-His binding energies in iron porphyrin FeP(His)(AB), myoglobin Mb(AB), H-NOX(AB), and Tyr140 → Phe mutated H-NOX[Y140F(AB)] were determined for comparison. The calculated stabilization of bound O2 is even higher in H-NOX than that in a myoglobin (Mb), consistent with the observation that the H-NOX domain of T. tengcongensis has a ver

SUBMITTER: Liao MS 

PROVIDER: S-EPMC3810174 | biostudies-literature | 2013 Sep

REPOSITORIES: biostudies-literature