@article{mbs:/content/journal/jgv/10.1099/0022-1317-82-10-2559, author = "Pant, V. and Gupta, D. and Choudhury, N. Roy and Malathi, V. G. and Varma, A. and Mukherjee, S. K.", title = "Molecular characterization of the Rep protein of the blackgram isolate of Indian mungbean yellow mosaic virus", journal= "Journal of General Virology", year = "2001", volume = "82", number = "10", pages = "2559-2567", doi = "https://doi.org/10.1099/0022-1317-82-10-2559", url = "https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-82-10-2559", publisher = "Microbiology Society", issn = "1465-2099", type = "Journal Article", abstract = "The complete nucleotide sequence of the blackgram isolate of mungbean yellow mosaic virus, IMYMV-Bg, which infects legumes in India, was determined and compared at the amino acid level with those of other whitefly-transmitted geminiviruses. The genome organization of IMYMV-Bg was similar to that of the begomoviruses. A unique feature of the genome organization was the sequence divergence of the common region (CR) between DNA-A and DNA-B. In order to understand the mechanism of viral DNA replication, the replication initiator protein, Rep, of IMYMV-Bg was overexpressed in E. coli. The recombinant and refolded Rep bound to CR-sequences of IMYMV-Bg in a specific manner. In this study, evidence is presented for ATP-upregulated cleavage function and ATP-mediated conformational change of Rep. It is hypothesized that, although ATP is not required for cleavage, ATP-mediated conformational changes may result in better access of Rep to the DNA-cleavage site. Evidence is also presented for a site-specific topoisomerase function of Rep, which has not been demonstrated before. The Rep protein can be classified as a type-I topoisomerase because of its nicking activity and sensitivity towards camptothecin, a topoisomerase type-I inhibitor.", }