Coat protein of cauliflower mosaic virus binds to ssDNA.
Alkali-denatured cauliflower mosaic virus (CaMV) virions incorporated ssDNA, added exogenously, into multimolecular complexes during dialysis against a neutral buffer. CaMV coat protein binding to tracer DNA, assessed by gel electrophoresis and autoradiography, was highly cooperative as judged by the absence of intermediate-sized complexes. The incorporation of labelled BglII fragments of a plasmid containing CaMV DNA into complexes was prevented by the presence of 0.16 g/l unlabelled calf thymus DNA. Lower concentrations of competitor DNA allowed binding of some BglII fragments although preventing the binding of others. The self-annealing poly(dI-dC) was much less efficient than calf thymus DNA in preventing the incorporation of fragments into complexes, suggesting a binding preference for ss- over dsDNA. In addition, dsDNA, minimally cross-linked to prevent strand separation, was bound only weakly. End-labelled ssDNA fragments in complexes were partially protected against DNase I. The nucleic acid-binding activity of CaMV coat protein may be responsible for the organization of replication complexes, the precursors to virion particles.
Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater 74078-0454.
S R
SR
Thompson
U
U
Melcher
D001667:Binding, Competitive; D001937:Brassica / Q000382:microbiology; D002213:Capsid / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000378:metabolism*; D004279:DNA, Viral / Q000378:metabolism*; D003850:Deoxyribonuclease I / Q000378:metabolism; D009029:Mosaic Viruses / Q000378:metabolism*
D004277:DNA, Single-Stranded; D004279:DNA, Viral; D003850:Deoxyribonuclease I