Lack of association of G-protein beta 2- and gamma 2-subunit N-terminal fragments provides evidence against the coiled-coil model of subunit-beta gamma assembly.
The association between peptides from bovine G-protein beta 2- and gamma 2-subunits was studied by CD spectroscopy and cross-linking. Both peptides had approximately 25% stable alpha-helical structure at 25 degrees C, but there was no increase on mixing subunits as expected for coiled-coil formation. Also, disulphide cross-linking gave more beta 2 beta 2 homodimer than beta 2 gamma 2 heterodimer. These data do not support the proposed N-terminal coiled-coil model of beta gamma-subunit association.
Marin
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EP
Department of Pharmacology, University of Michigan, Ann Arbor 48109-0632, USA.
Neubig
R R
RR
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D003432:Cross-Linking Reagents; D004220:Disulfides / Q000737:chemistry*; D019204:GTP-Binding Proteins / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry*; D011487:Protein Conformation
D003432:Cross-Linking Reagents; D004220:Disulfides; D010446:Peptide Fragments; D019204:GTP-Binding Proteins