Thermostability of membrane protein helix–helix interaction elucidated by statistical analysis

FEBS Letters

Engelman, Donald M¹  Liu, Yang¹  Schneider, Dirk¹  Gerstein, Mark¹ 

[1] Department of Molecular Biophysics and Biochemistry, Yale University, P.O. Box 208114, New Haven, CT 06520-8114, USA

关键词: Thermostability;    Sequence analysis;    Transmembrane helix;    Genome;    Mesophilic;    Thermophilic;   

DOI  :  10.1016/S0014-5793(02)03687-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A prerequisite for the survival of (micro)organisms at high temperatures is an adaptation of protein stability to extreme environmental conditions. In contrast to soluble proteins, where many factors have already been identified, the mechanisms by which the thermostability of membrane proteins is enhanced are almost unknown. The hydrophobic membrane environment constrains possible stabilizing factors for transmembrane domains, so that a difference might be expected between soluble and membrane proteins. Here we present sequence analysis of predicted transmembrane helices of the genomes from eight thermophilic and 12 mesophilic organisms. A comparison of the amino acid compositions indicates that more polar residues can be found in the transmembrane helices of thermophilic organisms. Particularly, the amino acids aspartic acid and glutamic acid replace the corresponding amides. Cysteine residues are found to be significantly decreased by about 70% in thermophilic membrane domains suggesting a non-specific function of most cysteine residues in transmembrane domains of mesophilic organisms. By a pair-motif analysis of the two sets of transmembrane helices, we found that the small residues glycine and serine contribute more to transmembrane helix–helix interactions in thermophilic organisms. This may result in a tighter packing of the helices allowing more hydrogen bond formation.

【 授权许可】

Unknown