Differences of reconstitution process between tobacco mosaic virus and cucumber green mottle mosaic virus by synchrotron small angle X-ray scattering using low-temperature quenching.

The differences of the reconstitution process of tobacco mosaic virus (TMV) and its mutant, cucumber green mottle mosaic virus (CGMMV) were investigated by the solution X-ray scattering measurements with the synchrotron radiation source using low-temperature quenching. The reconstitution in an aqueous solution is completely stopped below 5 degrees C. The TMV and CGMMV assembly was traced by the small-angle X-ray scattering (SAXS) measurements at 5 degrees C on a series of solutions prepared by low-temperature quenching after incubation at 20 degrees C for an appropriate interval between 0 and 60 min. The SAXS results were analyzed by the Guinier plot, the Kratky plot and the distance distribution function. The incubation of RNA and protein of CGMMV did not reconstitute at the initial reaction stages below 5 min and then began to reconstitute gradually. After 60 min, the radius of gyration for CGMMV reconstitution process reached almost the value for the initial stage of TMV reconstitution process. This is due to the fact the formation of double-layered disk in CGMMV protein is much slower than in TMV protein.