Rop protein

Rop (also known as repressor of primer) is a small homodimeric four-helix bundle protein formed by the antiparallel interaction of two helix-turn-helix monomers. The protein is expressed in Escherichia coli as a mechanism for regulating the gene copy numbers of plasmids. The Rop protein's structure has been solved to high resolution.^[1] Due to its small size and known structure, Rop has been used in protein design work to rearrange its helical topology and reengineer its loop regions.^[2] In general, the four-helix bundle has been extensively used in de novo protein design work as a simple model to understand the relationship between amino acid sequence and structure.

References

1. ^ Banner DW, Kokkinidis M, Tsernoglou D. (1987). Structure of the ColE1 rop protein at 1.7 A resolution. J Mol Biol 196(3):657-75.
2. ^ Kresse HP, Czubayko M, Nyakatura G, Vriend G, Sander C, Bloecker H. (2001). Four-helix bundle topology re-engineered: monomeric Rop protein variants with different loop arrangements. Protein Eng 14(11):897-901.