This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1mwm
From Proteopedia
ParM from plasmid R1 ADP form
Overview
It was the general belief that DNA partitioning in prokaryotes is independent of a cytoskeletal structure, which in eukaryotic cells is indispensable for DNA segregation. Recently, however, immunofluorescence microscopy revealed highly dynamic, filamentous structures along the longitudinal axis of Escherichia coli formed by ParM, a plasmid-encoded protein required for accurate segregation of low-copy-number plasmid R1. We show here that ParM polymerizes into double helical protofilaments with a longitudinal repeat similar to filamentous actin (F-actin) and MreB filaments that maintain the cell shape of non-spherical bacteria. The crystal structure of ParM with and without ADP demonstrates that it is a member of the actin family of proteins and shows a domain movement of 25 degrees upon nucleotide binding. Furthermore, the crystal structure of ParM reveals major differences in the protofilament interface compared with F-actin, despite the similar arrangement of the subunits within the filaments. Thus, there is now evidence for cytoskeletal structures, formed by actin-like filaments that are involved in plasmid partitioning in E.coli.
About this Structure
1MWM is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
F-actin-like filaments formed by plasmid segregation protein ParM., van den Ent F, Moller-Jensen J, Amos LA, Gerdes K, Lowe J, EMBO J. 2002 Dec 16;21(24):6935-43. PMID:12486014 Page seeded by OCA on Sat May 3 01:48:25 2008
