Crystallographic structure determination of B10 mutants of Vitreoscilla hemoglobin: role of Tyr29 (B10) in the structure of the ligand-binding site.

ABSTRACT: Site-directed mutants of the gene encoding wild-type Vitreoscilla hemoglobin were made that changed Tyr29 (B10) of the wild-type Vitreoscilla hemoglobin (VHb) to either Phe or Ala. The wild-type and the two mutant hemoglobins were expressed in Escherichia coli and purified to homogeneity. The binding of the two mutants to CO was essentially identical to that of wild-type VHb as determined by CO-difference spectra. Circular-dichroism spectra also showed the two mutants to be essentially the same as wild-type VHb regarding overall helicity. All three VHbs were crystallized and their structures were determined at resolutions of 1.7-1.9 Å, which are similar to that of the original wild-type structure determination. The Tyr29Phe mutant has a structure that is essentially indistinguishable from

SUBMITTER: Ratakonda S 

PROVIDER: S-EPMC3606562 | biostudies-literature | 2013 Mar

REPOSITORIES: biostudies-literature