HIGH-ALTITUDE RESPIRATION OF BIRDS - STRUCTURAL ADAPTATIONS IN THE MAJOR AND MINOR HEMOGLOBIN COMPONENTS OF ADULT RUPPELLS GRIFFON (GYPS-RUEPPELLII, AEGYPIINAE) - A NEW MOLECULAR-PATTERN FOR HYPOXIC TOLERANCE .120.
HIGH-ALTITUDE RESPIRATION OF BIRDS - STRUCTURAL ADAPTATIONS IN THE MAJOR AND MINOR HEMOGLOBIN COMPONENTS OF ADULT RUPPELLS GRIFFON (GYPS-RUEPPELLII, AEGYPIINAE) - A NEW MOLECULAR-PATTERN FOR HYPOXIC TOLERANCE .120.
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DOI：
10.1515/bchm3.1988.369.1.217
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发表时间：
1988-04-01
期刊：
影响因子：
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通讯作者：
BRAUNITZER, G
中科院分区：
文献类型：
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作者：
HIEBL, I;WEBER, RE;BRAUNITZER, G
介绍了飞行高度高达 11 300 m 的鲁佩尔狮鹫 (Gyps rueppellii) 血红蛋白 Hb A、Hb A''、Hb D 和 Hb D'' 的主要结构。珠蛋白链在 8M 尿素缓冲液中的 CM 纤维素上分离，四种血红蛋白成分在磷酸盐缓冲液中通过 FPLC 分离。通过在液相和气相测序仪中对珠蛋白链和胰蛋白酶肽进行自动 Edman 降解，建立了五个珠蛋白链的氨基酸序列。将这些序列与其他隼形目的序列进行比较。提出了一种在极端海拔下生存的新分子模式。首次在鸟类血液中发现四种血红蛋白；它们显示相同的β链，并且αA链和αD链仅通过一种替换而不同。这四种血红蛋白导致氧亲和力梯度。两个主要成分 Hb A 和 Hb A'' 在位置 α 处不同。 34 苏/岛。在Hb A''中发现的Ile的情况下，与Hb A相比，α1.β1-界面被中断，提高了氧亲和力。此外，A-和D-组的血红蛋白在位置α38 Pro或Gln/Thr（α1.β2-界面）处不同。与 Hb A/A'' 相比，Hb D/D'' 中 Gln 的表达通过脱氧结构的不稳定提高了这些成分的氧亲和力。其生理优势在于四种血红蛋白成分的功能相互作用。预测了三种亲和力水平：低亲和力 Hb A、中等亲和力的 Hb A'' 和高亲和力 Hb D/D''。该级联与在分离的组分中测量的氧亲和力精确相符，并预测复合血红蛋白在扩展的氧亲和力范围内的氧运输。有人认为，α-基因组复制（产生四种血红蛋白）和核苷酸替代（产生不同的功能特性）的机制是造成这种对 11 300 m 高度低氧耐受性的原因。根据这种模式，可以预测其他秃鹫的缺氧耐受性。
The primary structures of the hemoglobins Hb A, Hb A'', Hb D and Hb D'' of Ruppell''s Griffon (Gyps rueppellii), which can fly as high as 11 300 m, are presented. The globin chains were separated on CM-Cellulose in 8M urea buffers, the four hemoglobin components by FPLC in phosphate buffers. The amino-acid sequences of five globin chains were established by automatic Edman degradation of the globin chains and of the tryptic peptides in liquid-phase and gas-phase sequenators. The sequences are compared with those of other Falconiformes. A new molecular pattern for survival at extreme altitudes is presented. For the first time four hemoglobins are found in blood of a bird; they show identical .beta.-chains and differ in the .alpha.A- and .alpha.D-chains by only one replacement. These four hemoglobins cause a gradient in oxygen affinities. The two main components Hb A and Hb A'' differ at position .alpha. 34 Thr/Ile. In case of Ile as found in Hb A'' and .alpha.1.beta.1-interface is interrupted raising oxygen affinity compared to Hb A. In addition the hemoglobins of the A- and D-groups differ at position .alpha.38 Pro or Gln/Thr (.alpha.1.beta.2-interface). Expression of Gln in Hb D/D'' raises the oxygen affinity of these components compared to Hb A/A'' by destabilization of the deoxy-structure. The physiological advantage lies in the functional interplay of four hemoglobin components. Three levels of affinity are predicted: low affinity Hb A, Hb A'' of intermediate affinity, and high affinity Hb D/D''. This cascade tallies exactly with oxygen affinites measured in the isolated components and predicts oxygen transport by the composite hemoglobins over an extended range of oxygen affinities. It is contended that the mechanisms of duplication of the .alpha.-genome (creating four hemoglobins) and of nucleotide replacements (creating different functional properties) are responsible for this remarkable hypoxic tolerance to 11 300 m. Based on this pattern the hypoxic tolerances of other vultures are predicted.