Send to

Choose Destination
See comment in PubMed Commons below
J Biol Chem. 1992 Apr 15;267(11):7683-9.

Glycophorin A dimerization is driven by specific interactions between transmembrane alpha-helices.

Author information

Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511.


Specific side-by-side interactions between transmembrane alpha-helices may be important in the assembly and function of integral membrane proteins. We describe a system for the genetic and biophysical analysis of these interactions. The transmembrane alpha-helical domain of interest is fused to the C-terminus of staphylococcal nuclease. The resulting chimera can be expressed at high levels in Escherichia coli and is readily purified. In our initial application we study the single transmembrane alpha-helix of human glycophorin A (GpA), thought to mediate the SDS-stable dimerization of this protein. The resulting chimera forms a dimer in SDS, which is disrupted upon addition of a peptide corresponding to the transmembrane domain of GpA. Deletion mutagenesis has been used to delineate the minimum transmembrane domain sufficient for this behavior. Site-specific mutagenesis shows that a methionine residue, previously implicated as a potential interfacial residue, can be replaced with other hydrophobic residues without disrupting dimerization. By contrast, rather conservative substitutions at a valine on a different face of the alpha-helix disrupt dimerization, suggesting a high degree of specificity in the helix-helix interactions. This approach allows the interface between interacting helices to be defined.

[Indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire
    Loading ...
    Support Center