DNA複製開始タンパク質RepEの構造と機能

抄録

The RepE initiator protein of F plasmid plays an essential role in initiating DNA replication in mini-F origin. RepE exhibits two major functions; the RepE monomer plays as a replication initiator which binds to direct repeats (iterons) in origin, while the RepE dimer as an autogenous repressor to the repE operator. The crystal structure of RepE monomer (RepE54) as a complex with an iteron DNA was determined as the first 3-D structure for procaryotic initiator proteins. The RepE monomer consists of topologically similar N- and C-terminal domains related by an internal pseudo two-fold symmetry, which has not been expected from its amino acid sequence. Both domains bind to two major grooves of iteron (19bp) with different binding affinities. The C-terminal domain plays the leading role in this binding, while the N-terminal domain has the additional role in dimerization.