A Ser residue influences the structure and stability of a Pro-kinked transmembrane helix dimer

作者：Weber Mathias; Tome Lydia; Otzen Daniel; Schneider Dirk^*

来源：Biochimica et Biophysica Acta-Biomembranes, 2012, 1818(9): 2103-2107.

DOI：10.1016/j.bbamem.2012.04.003

• Cofactor binding
• Helix interaction
• Membrane protein
• Protein folding
• Protein stability
• Transmembrane helix

When localized adjacent to a Pro-kink, Thr and Ser residues can form hydrogen bonds between their polar hydroxyl group and a backbone carbonyl oxygen and thereby modulate the actual bending angle of a distorted transmembrane alpha-helix. We have used the homo-dimeric transmembrane cytochrome b(559)%26apos; to analyze the potential role of a highly conserved Set residue for assembly and stabilization of transmembrane proteins. Mutation of the conserved Ser residue to Ala resulted in altered heme binding properties and in increased stability of the holo-protein, most likely by tolerating subtle structural rearrangements upon heme binding. The results suggest a crucial impact of an intrahelical Set hydrogen bond in defining the structure of a Pro-kinked transmembrane helix dimer.

• 出版日期2012-9