Structure of the influenza C virus CM2 protein transmembrane domain obtained by site-specific infrared dichroism and global molecular dynamics searching.
The 115-residue protein CM2 from Influenza C virus has been recently characterized as a tetrameric integral membrane glycoprotein. Infrared spectroscopy and site-directed infrared dichroism were utilized here to determine its transmembrane structure. The transmembrane domain of CM2 is alpha-helical, and the helices are tilted by beta = (14.6 +/- 3.0) degrees from the membrane normal. The rotational pitch angle about the helix axis omega for the 1-(13)C-labeled residues Gly(59) and Leu(66) is omega = (218 +/- 17) degrees, where omega is defined as zero for a residue pointing in the direction of the helix tilt. A detailed structure was obtained from a global molecular dynamics search utilizing the orientational data as an energy refinement term. The structure consists of a left-handed coiled-coil with a helix crossing angle of Omega = 16 degrees. The putative transmembrane pore is occluded by the residue Met(65). In addition hydrogen/deuterium exchange experiments show that the core is not accessible to water.
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Cambridge Center for Molecular Recognition, Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, United Kingdom.
Arkin
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D003903:Deuterium; D006859:Hydrogen; D009982:Gammainfluenzavirus / Q000737:chemistry*; D008562:Membrane Glycoproteins / Q000737:chemistry; D008958:Models, Molecular; D010446:Peptide Fragments / Q000737:chemistry; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared; D014763:Viral Matrix Proteins / Q000737:chemistry*; D014764:Viral Proteins / Q000737:chemistry
C090877:CM2 protein, Influenza C virus; D008562:Membrane Glycoproteins; D010446:Peptide Fragments; D014763:Viral Matrix Proteins; D014764:Viral Proteins; D006859:Hydrogen; D003903:Deuterium