Kastritis Panagiotis L, Papandreou Nikos C, Hamodrakas Stavros J
Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Athens 157 01, Greece.
Int J Biol Macromol. 2007 Oct 1;41(4):447-53. doi: 10.1016/j.ijbiomac.2007.06.005. Epub 2007 Jun 19.
Proteins of halophilic archaea function in high-salt concentrations that inactivate or precipitate homologous proteins from non-halophilic species. Haloadaptation and the mechanism behind the phenomenon are not yet fully understood. In order to obtain useful information, homology modeling studies of dihydrofolate reductases (DHFRs) from halophilic archaea were performed that led to the construction of structural models. These models were subjected to energy minimization, structural evaluation and analysis. Complementary approaches concerning calculations of the amino acid composition and visual inspection of the surfaces and cores of the models, as well as calculations of electrostatic surface potentials, in comparison to non-halophilic DHFRs were also performed. The results provide evidence that sheds some light on the phenomenon of haloadaptation: DHFRs from halophilic archaea may maintain their fold, in high-salt concentrations, by sharing highly negatively charged surfaces and weak hydrophobic cores.
嗜盐古菌的蛋白质在高盐浓度下起作用，这种浓度会使来自非嗜盐物种的同源蛋白质失活或沉淀。盐适应性及其背后的机制尚未完全了解。为了获得有用的信息，对嗜盐古菌的二氢叶酸还原酶（DHFR）进行了同源建模研究，从而构建了结构模型。这些模型经过了能量最小化、结构评估和分析。还采用了补充方法，包括计算氨基酸组成、直观检查模型的表面和核心以及计算静电表面电位，并与非嗜盐DHFR进行比较。结果提供了一些关于盐适应性现象的线索：嗜盐古菌的DHFR在高盐浓度下可能通过共享高度带负电荷的表面和较弱疏水核心来维持其折叠结构。
