Tame J R, Wilson J C, Weber R E
Department of Chemistry, University of York, Helsington, UK.
J Mol Biol. 1996 Jun 21;259(4):749-60. doi: 10.1006/jmbi.1996.0355.
We have determined the X-ray crystallographic structure of trout Hb I in both the deoxy and carbonmonoxy forms to resolution limits of 2.3 angstroms and 2.5 angstroms, respectively. The overall fold of the molecule is highly similar to that of human HbA despite the low level of sequence identity between these proteins. Trout Hb I is unusual in displaying almost no pH dependence of oxygen binding affinity, and (at most) very weak interactions with heterotropic effector ligands such as organic phosphates. Comparison of the two quaternary states of the protein indicates how such effects are minimised and how the low-affinity T state of the protein is stabilised in the absence of heterotropic interactions.
我们已经确定了鳟鱼血红蛋白I（trout Hb I）的脱氧形式和一氧化碳结合形式的X射线晶体结构，分辨率分别达到2.3埃和2.5埃。尽管这些蛋白质之间的序列同一性水平较低，但分子的整体折叠与人类血红蛋白A（human HbA）高度相似。鳟鱼血红蛋白I的不同寻常之处在于，其氧结合亲和力几乎不显示pH依赖性，并且（至多）与异源效应配体（如有机磷酸盐）的相互作用非常微弱。对该蛋白质两种四级状态的比较表明了这些效应是如何最小化的，以及在没有异源相互作用的情况下，该蛋白质的低亲和力T态是如何稳定的。
