THE ATOMIC-STRUCTURE OF CARNATION MOTTLE VIRUS CAPSID PROTEIN

The structure of the Carnation Mottle Virus (CMtV) capsid protein has been determinated at 3.2 Angstrom resolution by the method of molecula r replacement. Three-dimensional data were collected from a small numb er of crystals (sp.g. 123, a = 382.6 Angstrom) using the synchrotron r adiation with an image plate as detector. The coordinates of Tomato Bu shy Stunt Virus (TBSV) were used as a searching model. Refinement of t he coordinates of 7,479 non-hydrogen atoms performed by the program XP LOR, has led to an R-factor of 18.3%. It was found that the amino acid chain fold of capsid protein is very similar to that in other icosahe dral viruses. However, there are some differences in the contact regio ns between protein subunits and also the lack of the beta-annulus arou nd the 3-fold icosahedral axes. The structural and biochemical results lead us to consider an alternative assembly pathway.