Interaction of haptoglobin with hemoglobin octamers based on the mutation αAsn78Cys or βGly83Cys.

ABSTRACT: Octameric hemoglobins have been developed by the introduction of surface cysteines in either the alpha or beta chain. Originally designed as a blood substitute, we report here the structure and ligand binding function; in addition the interaction with haptoglobin was studied. The recombinant Hbs (rHbs) with mutations alpha Asn78Cys or beta Gly83Cys spontaneously form octamers under conditions where the cysteines are oxidized. Oxygen binding curves and CO kinetic studies indicate a correct allosteric transition of the tetramers within the octamer. Crystallographic studies of the two rHbs show two disulfide bonds per octamer. Reducing agents may provoke dissociation to tetramers, but the octamers are stable when mixed with fresh human plasma, indicating that the reduction by plasma is slower

SUBMITTER: Brillet T 

PROVIDER: S-EPMC3706102 | biostudies-literature | 2012 Apr

REPOSITORIES: biostudies-literature