title: Conformational and aggregational properties of the gene 9 minor coat protein of bacteriophage M13 in membrane-mimicking systems.
abstract: The membrane-bound state of the gene 9 minor coat protein of bacteriophage M13 was studied in various membrane-mimicking systems, including organic solvents, detergent micelles, and phospholipid bilayers. For this purpose we determined the conformational and aggregational properties of the chemically synthesized protein by CD, FTIR, and HPSEC. The protein appears to be in a monomeric or small oligomeric alpha-helical state in TFE but adopts a mixture of alpha-helical and random structure after subsequent incorporation into SDS or DOPG. When solubilized by sodium cholate, however, the protein undergoes a transition in time into large aggregates, which contain mainly beta-sheet conformation. The rate of this beta-polymerization process was decreased at lower temperature and higher concentrations of sodium cholate. This aggregation was reversed only upon addition of high concentrations of the strong detergent SDS. By reconstitution of the cholate-solubilized protein into DOPG, it was found that the state of the protein, whether initially alpha-helical monomeric/oligomeric or beta-sheet aggregate, did not change. On the basis of our results, we propose that the principal conformational state of membrane-bound gene 9 protein in vivo is alpha-helical.
authors.affiliation: Department of Biomolecular Sciences, Laboratory of Molecular Physics, Wageningen University and Research Center, The Netherlands. chantal.houbiers@virus.mf.wau.nl
authors.forename: M C
authors.initials: MC
authors.lastname: Houbiers
authors.forename: R B
authors.initials: RB
authors.lastname: Spruijt
authors.forename: C J
authors.initials: CJ
authors.lastname: Wolfs
authors.forename: M A
authors.initials: MA
authors.lastname: Hemminga
mesh_terms: D000595:Amino Acid Sequence; D017104:Bacteriophage M13 / Q000737:chemistry* / Q000235:genetics; D002213:Capsid / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D036022:Capsid Proteins; D020355:Cholates / Q000737:chemistry; D002850:Chromatography, Gel; D002942:Circular Dichroism; D003902:Detergents / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry; D008567:Membranes, Artificial; D008969:Molecular Sequence Data; D010715:Phosphatidylglycerols / Q000737:chemistry; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D012995:Solubility; D014270:Trifluoroethanol / Q000737:chemistry
chemical_list: D036022:Capsid Proteins; D020355:Cholates; D003902:Detergents; D008051:Lipid Bilayers; D008567:Membranes, Artificial; D010715:Phosphatidylglycerols; C117230:gene 9 minor coat protein, bacteriophage M13; C051388:1,2-dioleoyl-sn-glycero-3-phosphoglycerol; D014270:Trifluoroethanol