Bimodal activation of SMC ATPase by intra- and inter-molecular interactions.

Journal Article (Journal Article)

Structural maintenance of chromosomes (SMC) proteins play fundamental roles in higher-order chromosome dynamics from bacteria to humans. It has been proposed that the Bacillus subtilis SMC (BsSMC) homodimer is composed of two anti-parallel coiled-coil arms, each having an ATP-binding domain at its distal end. It remains totally unknown, however, how the two-armed structure supports ATP-dependent actions of BsSMC. By constructing a number of mutant derivatives including 'single-armed' BsSMC, we show here that the central hinge domain provides a structural flexibility that allows opening and closing of the two arms. This unique structure brings about bimodal regulation of the SMC ATPase cycle. Closing the arm can trigger ATP hydrolysis by allowing an end-end interaction within a dimer (intramolecular mode). When bound to DNA, ATP promotes a dimer-dimer interaction, which in turn activates their DNA-dependent ATPase activity (intermolecular mode). Our results reveal a novel mechanism of ATPase regulation and provide mechanistic insights into how eukaryotic SMC protein complexes could mediate diverse chromosomal functions, such as chromosome condensation and sister chromatid cohesion.

Full Text

Duke Authors

Cited Authors

  • Hirano, M; Anderson, DE; Erickson, HP; Hirano, T

Published Date

  • June 15, 2001

Published In

Volume / Issue

  • 20 / 12

Start / End Page

  • 3238 - 3250

PubMed ID

  • 11406600

Pubmed Central ID

  • PMC150201

International Standard Serial Number (ISSN)

  • 0261-4189

Digital Object Identifier (DOI)

  • 10.1093/emboj/20.12.3238


  • eng

Conference Location

  • England