title: A fragment of recombinant GABA(A) receptor alpha1 subunit forming rosette-like homo-oligomers.
abstract: The type A gamma-aminobutyric acid (GABA(A)) receptor plays a major role in inhibitory synaptic transmission in the central nervous system. A fragment consisting of residues Cys166 to Leu296 of the alpha1 subunit of the GABA(A) receptor was overexpressed in Escherichia coli and was found to have stable beta-rich structures. Here, results from laser scattering, gel electrophoresis and electron microscopy demonstrated that this recombinant protein formed rosette-like homo-oligomers, mainly pentamers in solution. Therefore, the fragment apparently provides a valuable model system for studying the pentameric holoreceptor assembly. Non-reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis of the fragment showed that disulfide bonds formed between monomers contributed to the oligomerization of the fragment. The fact that this fragment alone could form pentamers in vitro strongly suggests that amino acid residues located within the Cys166-Leu296 region of the alpha1 subunit may contribute to the oligomerization of GABA(A) receptor in vivo.
authors.affiliation: Department of Biochemistry, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, P.R. China. hxue@ust.hk
authors.forename: H
authors.initials: H
authors.lastname: Xue
authors.forename: H
authors.initials: H
authors.lastname: Zheng
authors.forename: H M
authors.initials: HM
authors.lastname: Li
authors.forename: A
authors.initials: A
authors.lastname: Kitmitto
authors.forename: H
authors.initials: H
authors.lastname: Zhu
authors.forename: P
authors.initials: P
authors.lastname: Lee
authors.forename: A
authors.initials: A
authors.lastname: Holzenburg
mesh_terms: D000818:Animals; D002417:Cattle; D004220:Disulfides / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D007834:Lasers; D008854:Microscopy, Electron; D008970:Molecular Weight; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism*; D020836:Protein Structure, Quaternary; D011963:Receptors, GABA-A / Q000737:chemistry* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012542:Scattering, Radiation
chemical_list: D004220:Disulfides; D010446:Peptide Fragments; D011963:Receptors, GABA-A; D011994:Recombinant Proteins