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Updated: Aug 17, 2026

Preparation and Delivery of Protein Microcrystals in Lipidic Cubic Phase for Serial Femtosecond Crystallography
Published on: September 20, 2016
Structure of the ColE1 rop protein at 1.7 A resolution
D W Banner1, M Kokkinidis, D Tsernoglou
1EMBL, Heidelberg, FRG.
Abstract:
Structural details of the Rop protein from plasmid ColE1 are presented, with a description of the X-ray crystal structure determination and refinement at a nominal resolution of 1.7 A. The 63 amino acid protein is a dimer. Each monomer consists almost entirely of two alpha helices, the whole molecule forming a highly regular four-alpha-helix bundle. This may be approximated by a four-stranded rope with a radius of 7.0 A, a left-handed helical twist and a pitch of 172.5 A. The packing constraints for this novel type of coiled-coil structure are given. The protein acts in the control of plasmid replication via regulation of an RNA-RNA interaction in a manner not yet understood in atomic detail.
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