title: A comparison of the solution structures of tobacco rattle and tobacco mosaic viruses from Raman optical activity.
abstract: Vibrational Raman optical activity (ROA) spectra of tobacco rattle virus (TRV) and tobacco mosaic virus (TMV) were measured and compared with a view to obtaining new information about the coat protein subunit structure of TRV. A sharp strong positive band observed at approximately 1344 cm(-1) in the ROA spectra of the two viruses is evidence that both contain a significant amount of a hydrated form of alpha-helix, but more in TRV than in TMV. Although the ROA spectrum of TMV shows significant positive intensity in the range approximately 1297-1312 cm(-1) characteristic of alpha-helix in a hydrophobic environment, as expected from the helix interface residues in the four-helix bundles that constitute the basic motif of the TMV coat protein fold, that of TRV shows little positive ROA intensity here. Instead TRV shows a strong positive ROA band at approximately 1315 cm(-1), of much greater intensity than bands shown here by TMV, that is characteristic of polyproline II (PPII) helix. This suggests that the additional long central and C-terminal sequences of the TRV coat proteins contain a significant amount of PPII structure, plus perhaps some beta-strand judging by a prominent sharp negative ROA band shown by TRV at approximately 1236 cm(-1), but little alpha-helix. The open flexible hydrated nature of PPII helical structure is consistent with the earlier suggestions that the additional sequences are exposed and, together with a larger amount of hydrated alpha-helix, could serve to fill the extra volume required by the larger diameter of the cylindrical TRV particles relative to those of TMV.
authors.affiliation: Department of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK1.
authors.forename: Ewan W
authors.initials: EW
authors.lastname: Blanch
authors.affiliation: Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, UK2.
authors.forename: David J
authors.initials: DJ
authors.lastname: Robinson
authors.affiliation: Department of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK1.
authors.forename: Lutz
authors.initials: L
authors.lastname: Hecht
authors.affiliation: Department of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK1.
authors.forename: Laurence D
authors.initials: LD
authors.lastname: Barron
mesh_terms: D002213:Capsid / Q000737:chemistry* / Q000378:metabolism; D036022:Capsid Proteins; D018583:Pliability; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D012328:RNA Viruses / Q000737:chemistry*; D012996:Solutions; D013059:Spectrum Analysis, Raman; D014027:Tobacco Mosaic Virus / Q000737:chemistry*; D014732:Vibration; D014764:Viral Proteins / Q000737:chemistry* / Q000378:metabolism
chemical_list: D036022:Capsid Proteins; C009496:H protein, Tobacco mosaic virus; D021122:Protein Subunits; D012996:Solutions; D014764:Viral Proteins; C085220:coat protein, Tobacco rattle virus