REP PROTEIN OF TOMATO YELLOW LEAF CURL GEMINIVIRUS HAS AN ATPASE ACTIVITY REQUIRED FOR VIRAL-DNA REPLICATION

The Rep protein of geminiviruses is the sole viral protein required fo r their DNA replication, The amino acid sequence of Rep protein contai ns an NTP binding consensus motif (P-loop), Here ne show that purified Rep protein of tomato yellow leaf curl virus expressed in Escherichia roll exhibits ATPase activity in vitro. Amino acid exchanges in the P -loop sequence of Rep causes a substantial decrease or loss of the ATP ase activity, In vivo, mutant viruses carrying these Rep mutations do not replicate in plant cells, These results show that ATP binding by t he Rep protein of geminiviruses is required for its function in viral DNA replication.