Probing the role of the backbone carbonyl interaction with the Cu_A center in azurin by replacing the peptide bond with an ester linkage.

ABSTRACT: The role of a backbone carbonyl interaction with an engineered Cu_A center in azurin was investigated by developing a method of synthesis and incorporation of a depsipeptide where one of the amide bonds in azurin is replaced by an ester bond using expressed protein ligation. Studies by electronic absorption and electron paramagnetic resonance spectroscopic techniques indicate that, while the substitution does not significantly alter the geometry of the site, it weakens the axial interaction to the Cu_A center and strengthens the Cu-Cu bond, as evidenced by the blue shift of the near-IR absorption that has been assigned to the Cu-Cu ψ → ψ* transition. Interestingly, the changes in the electronic structure from the replacement did not result in a change in the reduction p

SUBMITTER: Clark KM 

PROVIDER: S-EPMC5253137 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature