Site-directed mutagenesis in hemoglobin. Effect of some mutations at protein interfaces.
FEBS Lett
; 324(2): 117-22, 1993 Jun 14.
Article
en En
| MEDLINE
| ID: mdl-8508913
ABSTRACT
The role of selected amino acid residues in the monomer-monomer contacts of Hb A has been studied by site-directed mutagenesis of the alpha chain bearing substitutions in the subunit surfaces. Mutation alpha 38Thr-->Trp induced a stabilization of tetrameric Hb-CO with a decrease of the Kd for the equilibrium alpha 2 beta 2<==>2 alpha beta, but had not effect on ligand binding. Mutation alpha 40Thr-->Arg resulted in a complete loss of cooperativity in ligand binding. Mutation alpha 103His-->Val had no noticeable effect. We also studied the behaviour of isolated, mutated alpha chains with respect to self association compared to wt alpha chains, mutant alpha 38Thr-->Trp showed stabilization of the dimeric state and (at high protein concentration) a detectable amount of tetramers. Mutant alpha 103His-->Val showed only a minor stabilization of the alpha 2 dimer.
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Banco de datos:
MEDLINE
Asunto principal:
Hemoglobina A
Límite:
Humans
Idioma:
En
Año:
1993
Tipo del documento:
Article