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J Mol Biol. 2003 Dec 5;334(4):803-9.

Inter-helical hydrogen bond formation during membrane protein integration into the ER membrane.

Author information

1
Department of Biochemistry and Biophysics, Stockholm University, SE-106 91, Stockholm, Sweden.

Abstract

Recent work has shown that efficient di- or trimerization of hydrophobic transmembrane helices in detergent micelles or lipid bilayers can be driven by inter-helix hydrogen bonding involving polar residues such as Asn or Asp. Using in vitro translation in the presence of rough microsomes of a model integral membrane protein, we now show that the formation of so-called helical hairpins, two tightly spaced transmembrane helices connected by a short loop, can likewise be promoted by the introduction of Asn-Asn or Asp-Asp pairs in a long transmembrane hydrophobic segment. These observations suggest that inter-helix hydrogen bonds can form within the context of the Sec61 translocon in the endoplasmic reticulum, implying that hydrophobic segments in a nascent polypeptide chain in transit through the Sec61 channel have immediate access to a non-aqueous subcompartment within the translocon.

PMID:
14636604
[Indexed for MEDLINE]

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