Interaction of viral proteins with metal ions: role in maintaining the structure and functions of viruses.

Metal ions are integral part of some viral proteins and play an important role in their survival and pathogenesis. Zinc, magnesium and copper are the commonest metal ion that binds with viral proteins. Metal ions participate in maturation of genomic RNA, activation and catalytic mechanisms, reverse transcription, initial integration process and protection of newly synthesized DNA, inhibition of proton translocation (M2 protein), minus- and plus-strand transfer, enhance nucleic acid annealing, activation of transcription, integration of viral DNA into specific sites and act as a chaperone of nucleic acid. Metal ions are also required for nucleocapsid protein-transactivation response (TAR)-RNA interactions. In certain situations more than one metal ion is required e.g. RNA cleavage by RNase H. This review underscores the importance of metal ions in the survival and pathogenesis of a large group of viruses and studies on structural basis for metal binding should prove useful in the early design and development of viral inhibitors.