Conformational transitions of the three recombinant domains of human serum albumin depending on pH
Conformational transitions of the three recombinant domains of human serum albumin depending on pH
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DOI：
10.1074/jbc.275.5.3042
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发表时间：
2000-02-04
影响因子：
4.8
通讯作者：
Rüker, F
中科院分区：
文献类型：
--
作者：
Dockal, M;Carter, DC;Rüker, F
Human serum albumin (HSA) is a protein of 66.5 kDa that is composed of three homologous domains, each of which displays specific structural and functional characteristics. HSA is known to undergo different pH-dependent structural transitions, the N-F and F-E transitions in the acid pH region and the N-B transition at slightly alkaline pH, In order to elucidate the structural behavior of the recombinant HSA domains as stand-alone proteins and to investigate the molecular and structural origins of the pH-induced conformational changes of the intact molecule, we have employed fluorescence and circular dichroic methods. Here we provide evidence that the loosening of the HSA structure in the N-F transition takes place primarily in HSA-DOM III and that HSA-DOM I undergoes a structural rearrangement with only minor changes in secondary structure, whereas HSA-DOM II transforms to a molten globule-like state as the pH is reduced. In the pH region of the N-B transition of HSA, HSA-DOM I and HSA-DOM II experience a tertiary structural isomerization, whereas with HSA-DOM III no alterations in tertiary structure are observed, as judged from near-UV CD and fluorescence measurements.
