ISSN:
1573-4943
Keywords:
Hemoglobin
;
α–β chain association
;
oligomeric proteins
;
synthetic peptides
;
subunit interacting surfaces
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract By using synthetic overlapping peptides encompassing the entire α-chain of adult human hemoglobin (HbA), we have mapped on the α-chain the regions responsible for its binding to the β-chain in solution. These binding surfaces were, in general, in good agreement with those expected from the crystal structure (peptides α81–95, α101–115, α111–125, and α131–141). However, we observed some significant differences in the levels of binding found here in solution and those expected from the crystal structure. Peptide α31–45, which in the crystal had the highest number of contact residues of all the α-chain peptides, did not bind the β-chain in solution. Similarly, peptide α91–105, with seven contact residues in the crystal, showed low binding with the β-chain in solution. On the other hand, peptides α41–55 and α121–135 possessed much higher binding activity in solution than would be expected from their contribution to subunit association in the crystal. In fact, peptide α121–135 had the highest binding activity of the α-chain peptides. These studies and our previous findings, which localized on the β-chain the regions that bind to the α-chain in solution, have shown that the regions of subunit association in solution are close to, but not identical with, those in the crystal. The approach should be quite useful for mapping subunit association in oligomeric proteins and could even be applied to proteins that are isolated only in traces or whose three-dimensional structure is not yet known.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1020623905544
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