Rop (also known as repressor of primer) is a small protein responsible for keeping the copy number of ColE1 and related bacterial plasmids low in E. coli. Structurally, Rop is a homodimeric four-helix bundle protein formed by the antiparallel interaction of two helix-turn-helix monomers. 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.
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Rop protein Wikipedia(Text) CC BY-SA