Protein Domain : Regulatory protein Rop IPR000769

Type	Family
Description	The Rop protein regulates plasmid DNA replication by modulating the initiation of transcription of the primer RNA precursor. Processing of the precursor, RNAII, is inhibited by hydrogen bonding of RNAII to its complementary sequence in RNAI. Rop increases the affinity of RNAI for RNAII and thus decreases the rate of replication initiation events. The 3D structure of Rop has been determined by X-ray crystallography and refined to 1.7A resolution. The 63 amino acid protein is a homodimer, each monomer consisting almost entirely of two α-helices, the whole molecule forming a highly regular four-α-helix bundle [ ]. This can be approximated by a four-stranded rope, with radius 7.0 A, a left-handed helical twist, and pitch 172.5 A. A very compact packing of side chains in the helix interfaces of the Rop coiled-coil structure is presumed to account for its high stability [ ]. The overall details of the structure have beenconfirmed by proton NMR [ , ].
Short Name	Regulatory_Rop