文章基本信息

标题：Emission Mössbauer study of the stereochemical trigger that initiates cooperative interaction of hemoglobin subunits
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作者：T S Srivastava ; S Tyagi ; A Nath 等
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：1977
卷号：74
期号：11
页码：4996-5000
DOI：10.1073/pnas.74.11.4996
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：An important feature of Perutz's trigger mechanism for cooperativity in the reversible oxygenation of hemoglobin (Hb) is the tension along the histidine--metal linkage in deoxyHb and deoxycobaltohemoglobin (deoxy CoHb), supposedly due to the pull exerted by the globin on the metal atom. We have attempted to verify the existence of this pull by studying the emission Mossbauer spectra of deoxy 57CoHb and oxy 57 CoHb at different temperatures. The emission Mossbauer spectrum for none of the cobalt Hbs agrees with the absorption spectrum of the corresponding iron analog and, moreover, the spectrum of deoxy 57CoHb is characteristic of the intermediate-spin iron. These observations indicate that the daughter 57Fe atom is "frozen" almost in the same spatial situation as that of the parent 57Co. The protein is apparently holding the cobalt atom in position rather rigidly and, after the electron-capture decay of the 57Co atom, the protein does not permit the daughter 57Fe to move to a position characteristic of the iron atom.