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Visualization by atomic force microscopy of tobacco mosaic virus movement protein–RNA complexes formed in vitro

2001; Microbiology Society; Volume: 82; Issue: 6 Linguagem: Inglês

10.1099/0022-1317-82-6-1503

1465-2099

Olga I. Kiselyova, I. V. Yaminsky, Е. М. Каргер, Olga Frolova, Yuri L. Dorokhov, J.G. Atabekov,

Plant Virus Research Studies

The structure of complexes formed in vitro by tobacco mosaic virus (TMV)-coded movement protein (MP) with TMV RNA and short (890 nt) synthetic RNA transcripts was visualized by atomic force microscopy on a mica surface. MP molecules were found to be distributed along the chain of RNA and the structure of MP-RNA complexes depended on the molar MP:RNA ratios at which the complexes were formed. A rise in the molar MP:TMV RNA ratio from 20:1 to 60-100:1 resulted in an increase in the density of the MP packaging on TMV RNA and structural conversion of complexes from RNase-sensitive 'beads-on-a-string' into a 'thick string' form that was partly resistant to RNAse. The 'thick string'-type RNase-resistant complexes were also produced by short synthetic RNA transcripts at different MP:RNA ratios. The 'thick string' complexes are suggested to represent clusters of MP molecules cooperatively bound to discrete regions of TMV RNA and separated by protein-free RNA segments.