Molecular basis for a protein-mediated DNA-bridging mechanism that functions in condensation of the E. coli chromosome.
The E. coli chromosome is condensed into insulated regions termed macrodomains (MDs), which are essential for genomic packaging. How chromosomal MDs are specifically organized and compacted is unknown. Here, we report studies revealing the molecular basis for Terminus-containing (Ter) chromosome condensation by the Ter-specific factor MatP. MatP contains a tripartite fold with a four-helix bundle DNA-binding motif, ribbon-helix-helix and C-terminal coiled-coil. Strikingly, MatP-matS structures show that the MatP coiled-coils form bridged tetramers that flexibly link distant matS sites. Atomic force microscopy and electron microscopy studies demonstrate that MatP alone loops DNA. Mutation of key coiled-coil residues destroys looping and causes a loss of Ter condensation in vivo. Thus, these data reveal the molecular basis for a protein-mediated DNA-bridging mechanism that mediates condensation of a large chromosomal domain in enterobacteria.
Centre de Génétique Moléculaire du CNRS, Associé à l'Université Paris-Sud, 91198 Gif-sur-Yvette, France.
Pauline
P
Dupaigne
Nam K
NK
Tonthat
Olivier
O
Espéli
Travis
T
Whitfill
Frédéric
F
Boccard
Maria A
MA
Schumacher
D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D002876:Chromosomes, Bacterial / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D048168:Escherichia coli K12 / Q000166:cytology / Q000235:genetics* / Q000378:metabolism* / Q000648:ultrastructure; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D018625:Microscopy, Atomic Force; D008854:Microscopy, Electron; D008958:Models, Molecular; D011485:Protein Binding
D002868:Chromosomal Proteins, Non-Histone; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C533037:MatP protein, E coli