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：1980
卷号：77
期号：4
页码：2033-2037
DOI：10.1073/pnas.77.4.2033
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Resonance Raman spectra have been obtained of the alpha deoxy and beta deoxy subunits within valency hybrid hemoglobins both in the high-affinity (R) and low-affinity (T) structures. Upon conversion from the R to the T structure, the vibrational frequency of the Fe(II)-N epsilon(His-F8) bond changes from 223 to 207 or 203 cm-1 in the alpha deoxy subunit and from 224 to 220 or 217 cm-1 in the beta deoxy subunit. We estimate that the Fe(II)-N epsilon(His-F8) bond is stretched by the R leads to T transition 3 times more in the alpha subunit (0.024 A) than in the beta subunit (0.0085 A) and, accordingly, the strain energy developed in that bond is 8 times larger in the alpha than in the beta subunit. Hence, the oxygen affinity of the alpha and beta subunits may be regulated by different mechanisms.
