期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1982
卷号：79
期号：6
页码：1849-1853
DOI：10.1073/pnas.79.6.1849
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The sites of energy transduction within the human hemoglobin molecule for the regulation of oxygen affinity have been determined by an extensive study of the molecule's energetic response to structural alteration at individual amino acid residues. For 22 mutant and chemically modified hemoglobins we have determined the total free energy used by the tetrameric molecule for alteration of oxygen affinity at the four binding steps. The results imply that the regulation of oxygen binding affinity is due to energy changes which are mostly localized at the alpha 1 beta 2 interface. They also indicate a high degree of "internal cooperativity" within this contact region--i.e., the structural perturbations at individual residue sites are energetically coupled. Cooperativity in ligand binding is thus a reflection of cooperativity at a deeper level--that of the protein-protein interactions within the alpha 1 beta 2 interfacial domain.
