1mwk
From Proteopedia
ParM from plasmid R1 APO 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
1MWK 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 01:48:21 2008
