Genetic and structural analysis of the ColE1 Rop (Rom) protein

L. Castagnoli, M. Scarpa, M. Kokkinidis, D. W. Banner, D. Tsernoglou, G. Cesareni

Research output: Contribution to journalArticlepeer-review


Repressor of primer (Rop) is a small dimeric protein that participates in the mechanism that controls the copy number of plasmid of the ColE1 family by increasing the affinity between two complementary RNAs. The Rop dimer is a bundle of four tightly packed α-helices that are held together by hydrophobic interactions. We have systematically altered, by site directed mutagenesis, most of the solvent exposed amino acids of the Rop bundle and we have identified the alterations that cause a decrease of the activity of the regulatory molecule. We conclude that Rop folding is rather insensitive to amino acid substitutions and to other mutations as drastic as deletions and insertions. Looking along the 2-fold symmetry axis the amino acid side chains whose alterations affect the function of Rop are all located on one side of the molecule. Furthermore they are clustered at the extremities of the α-helix bundle, the only exception being the aromatic ring of Phe-14.

Original languageEnglish
Pages (from-to)621-629
Number of pages9
JournalEMBO Journal
Issue number2
Publication statusPublished - 1989

ASJC Scopus subject areas

  • Cell Biology
  • Genetics


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