Diving behaviour and haemoglobin function: the primary structure of the alpha- and beta-chains of the sea turtle (Caretta caretta) and its functional implications.
Diving behaviour and haemoglobin function: the primary structure of the alpha- and beta-chains of the sea turtle (Caretta caretta) and its functional implications.
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DOI：
10.1042/bj3160959
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发表时间：
1996-06
期刊：
影响因子：
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通讯作者：
R. Petruzzelli;G. Aureli;A. Lania;A. Galtieri;A. Desideri;B. Giardina
中科院分区：
文献类型：
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作者：
R. Petruzzelli;G. Aureli;A. Lania;A. Galtieri;A. Desideri;B. Giardina
红海龟血红蛋白(Hb) α链和β链的氨基酸序列已经确定。与人类Hb的比较显示了α 1 β 1和α 1 β 2包装接触中涉及的几个残基的差异。总的来说，尽管发生了突变，但两个界面的基本特征似乎都保持了下来。研究了海龟Hb在不同温度下的功能特性，以及质子、氯化物和有机磷酸盐浓度的函数。除了与之前描述的大多数脊椎动物Hbs有总体上的相似之处外，这种分子还显示出与海龟生活行为有关的显著差异。事实上，虽然玻尔效应曲线的形状很适合长时间潜水期间的气体交换，但O2结合的焓变化非常小，这确保了O2的输送对环境的温度变化基本上不敏感。此外，与帝企鹅Hb的情况类似，小碱性玻尔效应似乎只与氯离子相连，因为在没有离子的情况下，O2亲和力的pH依赖性被消除了。这些功能特征是在α链和β链一级结构的基础上讨论的。
The amino acid sequence of the alpha- and beta-chains of haemoglobin (Hb) from the loggerhead sea turtle (Caretta caretta) has been determined. Comparison with that of human Hb shows differences in several residues involved in both alpha 1 beta 1 and alpha 1 beta 2 packing contacts. On the whole, in spite of the mutations, the essential characteristics of both interfaces seem to be maintained. The functional properties of the sea turtle Hb have been investigated at different temperatures and as a function of proton, chloride and organic phosphate concentrations. In addition to overall similarities shared with most of the vertebrate Hbs previously described, this molecule shows significant differences which could be related to the life behaviour of the turtle. In fact, while the shape of the Bohr-effect curve is well adapted for gas exchange during prolonged dives, the very small enthalpy change for O2 binding ensures that O2 delivery becomes essentially insensitive to the temperature changes of the environment. Moreover, and similarly to the case of emperor penguin Hb, the small alkaline Bohr effect appears to be only choride-linked, since the pH dependence of the O2 affinity is abolished in the absence of this ion. These functional characteristics are discussed on the basis of the primary structure of alpha- and beta-chains.