Probing the Role of Murine Neuroglobin CDloop-D-Helix Unit in CO Ligand Binding and Structural Dynamics.

ABSTRACT: We produced a neuroglobin variant, namely, Ngb CDless, with the excised CDloop- and D-helix, directly joining the C- and E-helices. The CDless variant retained bis-His hexacoordination, and we investigated the role of the CDloop-D-helix unit in controlling the CO binding and structural dynamics by an integrative approach based on X-ray crystallography, rapid mixing, laser flash photolysis, resonance Raman spectroscopy, and molecular dynamics simulations. Rapid mixing and laser flash photolysis showed that ligand affinity was unchanged with respect to the wild-type protein, albeit with increased on and off constants for rate-limiting heme iron hexacoordination by the distal His64. Accordingly, resonance Raman spectroscopy highlighted a more open distal pocket in the CO complex that, in agre

SUBMITTER: Exertier C 

PROVIDER: S-EPMC9396615 | biostudies-literature | 2022 Aug

REPOSITORIES: biostudies-literature