α-Hemoglobin-stabilizing protein (AHSP) perturbs the proximal heme pocket of oxy-α-hemoglobin and weakens the iron-oxygen bond.

ABSTRACT: α-Hemoglobin (αHb)-stabilizing protein (AHSP) is a molecular chaperone that assists hemoglobin assembly. AHSP induces changes in αHb heme coordination, but how these changes are facilitated by interactions at the αHb·AHSP interface is not well understood. To address this question we have used NMR, x-ray absorption spectroscopy, and ligand binding measurements to probe αHb conformational changes induced by AHSP binding. NMR chemical shift analyses of free CO-αHb and CO-αHb·AHSP indicated that the seven helical elements of the native αHb structure are retained and that the heme Fe(II) remains coordinated to the proximal His-87 side chain. However, chemical shift differences revealed alterations of the F, G, and H helices and the heme pocket of CO-αHb bound to AHSP. Comparisons of iron-ligand

SUBMITTER: Dickson CF 

PROVIDER: S-EPMC3707698 | biostudies-literature | 2013 Jul

REPOSITORIES: biostudies-literature