Helix-helix packing in a membrane-like environment.
The unique ability of the glycophorin A transmembrane helix to dimerize in SDS has previously been exploited in studies of the sequence specificity of helix-helix packing in a micellar environment. Here, we have made different insertion mutants in the critical helix-helix interface segment, and find that efficient dimerization can be mediated by a wider range of sequence motifs than suggested by the earlier studies. We also show that certain mutants that are unable to dimerize can nevertheless form relatively high amounts of tetramers, and that specific tetramerization can be induced by duplication of the critical interface motif on the lipid-exposed side of the transmembrane helix.
Mingarro
I
I
Department of Biochemistry, Stockholm University, Stockholm, S-106 91, Sweden.
Elofsson
A
A
von Heijne
G
G
D000409:Alanine / Q000737:chemistry; D000595:Amino Acid Sequence; D019281:Dimerization; D004926:Escherichia coli; D006021:Glycophorins / Q000737:chemistry* / Q000235:genetics; D007930:Leucine / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D017433:Protein Structure, Secondary; D012967:Sodium Dodecyl Sulfate
D006021:Glycophorins; D008565:Membrane Proteins; D012967:Sodium Dodecyl Sulfate; D007930:Leucine; D000409:Alanine