Ligand binding kinetic studies on the hybrid hemoglobin alpha (human):beta (carp): a hemoglobin with mixed conformations and sequential conformational changes.
Ligand binding kinetic studies on the hybrid hemoglobin alpha (human):beta (carp): a hemoglobin with mixed conformations and sequential conformational changes.
复制标题
混合血红蛋白α（人）：β（鲤鱼）的配体结合动力学研究：具有混合构象和连续构象变化的血红蛋白。
DOI：
10.1021/bi00305a012
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发表时间：
1984
期刊：
影响因子：
2.9
通讯作者：
Goss,DJ
中科院分区：
文献类型：
--
作者：
Parkhurst,LJ;Goss,DJ
材料和方法按照上一篇论文（Goss & Parkhurst, 1984）的描述制备人血红蛋白和杂交血红蛋白。f内布拉斯加大学化学系，林肯，内布拉斯加州68588-03041983年5月9日收到；1983年11月15日收到改稿。本研究由NIH Grant HL 15,284， NSF Grant PCM 8003655和内布拉斯加大学研究委员会支持。8链首先具有t态性质，其次是“-链”。鲤鱼8链的RT构象变化率至少是人类8链的300倍。在pH为9时，R - * T的构象转变速率至少比人血红蛋白慢200倍。在这个pH值下，鲤鱼8链R态与一氧化碳的反应速度是鲤鱼血红蛋白的两倍。图表显示了动力学证据支持的所有构象。杂交体中的配体动力学表明，在鲤鱼血红蛋白中，“-链”阻止鲤鱼8-链获得完全的r态性质，并且本身偏向于T构象。鲤鱼8-链呈T态的显著趋势，有力地支持了8-链在根效应中起核心作用的模型[Perutz， M. F., & Brunori， M.(1982) Nature (London) 299, 421-426]。然而，从现有的数据来看，似乎不可能将一定数量的玻尔质子分配给鲤鱼和人类血红蛋白中的四个单独的链。
Materials and MethodsHuman hemoglobin and hybrid hemoglobins were prepared as described in the previous paper (Goss & Parkhurst, 1984). f From the Department of Chemistry, University of Nebraska, Lin-coln, Nebraska 68588-0304. Received May 9, 1983; revised manuscript received November 15, 1983. This research was supported by NIH Grant HL 15,284, NSF Grant PCM 8003655, and the Research Council, University of Nebraska. the 8-chains first assume T-state properties, followed by the «-chains. The rate of the RT conformational change for the carp 8-chains is at least 300 times greater than that for the human «-chains. At pH 9, the R—* T conformational tran-sition rate is at least 200 times slower thanthat for human hemoglobin. The carp 8-chain R state at this pH reacts twice as rapidly with CO as in carp hemoglobin. Diagrams are presented showing all conformations supported by kinetic evidence. The ligand kinetics in the hybrid suggest that in carp hemoglobin, the «-chains prevent the carp 8-chains from as-suming full R-state properties and are themselves biased to-ward the T conformation. The marked tendency of the carp 8-chains to assume the T state lends strong support to the model that assigns a central role to the 8-chain in the Root effect [Perutz, M. F., & Brunori, M.(1982) Nature (London) 299, 421-426], From the data at hand, however, it does not appear possible to assign a definite number of Bohr protons to the four individual chains in carp and human hemoglobins.