1Q5I

Crystal structure of bacteriorhodopsin mutant P186A crystallized from bicelles

1Q5I の概要

• エントリーDOI: 10.2210/pdb1q5i/pdb
• 関連するPDBエントリー: 1Q5J
• 分子名称: Bacteriorhodopsin, RETINAL (3 entities in total)
• 機能のキーワード: alpha helix, membrane protein
• 由来する生物種: Halobacterium salinarum
• 細胞内の位置: Cell membrane ; Multi-pass membrane protein : P02945
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 54375.80

構造登録者

Yohannan, S.,Faham, S.,Yang, D.,Whitelegge, J.P.,Bowie, J.U. (登録日: 2003-08-07, 公開日: 2004-01-06, 最終更新日: 2024-10-09)

主引用文献

Yohannan, S.,Faham, S.,Yang, D.,Whitelegge, J.P.,Bowie, J.U.
The evolution of transmembrane helix kinks and the structural diversity of G protein-coupled receptors.
Proc.Natl.Acad.Sci.USA, 101:959-963, 2004

PubMed Abstract: One of the hallmarks of membrane protein structure is the high frequency of transmembrane helix kinks, which commonly occur at proline residues. Because the proline side chain usually precludes normal helix geometry, it is reasonable to expect that proline residues generate these kinks. We observe, however, that the three prolines in bacteriorhodopsin transmembrane helices can be changed to alanine with little structural consequences. This finding leads to a conundrum: if proline is not required for helix bending, why are prolines commonly present at bends in transmembrane helices? We propose an evolutionary hypothesis in which a mutation to proline initially induces the kink. The resulting packing defects are later repaired by further mutation, thereby locking the kink in the structure. Thus, most prolines in extant proteins can be removed without major structural consequences. We further propose that nonproline kinks are places where vestigial prolines were later removed during evolution. Consistent with this hypothesis, at 14 of 17 nonproline kinks in membrane proteins of known structure, we find prolines in homologous sequences. Our analysis allows us to predict kink positions with >90% reliability. Kink prediction indicates that different G protein-coupled receptor proteins have different kink patterns and therefore different structures.

PubMed: 14732697
DOI: 10.1073/pnas.0306077101

実験手法

X-RAY DIFFRACTION (2.3 Å)