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ATP‐dependent aggregation of single‐stranded DNA by a bacterial SMC homodimer
Author(s) -
Hirano Michiko,
Hirano Tatsuya
Publication year - 1998
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/17.23.7139
Subject(s) - biology , dna , escherichia coli proteins , biophysics , genetics , bacterial protein , biochemistry , bacteria
SMC ( s tructural m aintenance of c hromosomes) proteins are putative ATPases that are highly conserved among Bacteria, Archaea and Eucarya. Eukaryotic SMC proteins are implicated in a diverse range of chromosome dynamics including chromosome condensation, dosage compensation and recombinational repair. In eukaryotes, two different SMC proteins form a heterodimer, which in turn acts as the core component of a large protein complex. Despite recent progress, no ATP‐dependent activity has been found in individual SMC subunits. We report here the first biochemical characterization of a bacterial SMC protein from Bacillus subtilis . Unlike eukaryotic versions, the B.subtilis SMC protein (BsSMC) is a simple homodimer with no associated subunits. It binds preferentially to single‐stranded DNA (ssDNA) and has a ssDNA‐stimulated ATPase activity. In the presence of ATP, BsSMC forms large nucleoprotein aggregates in a ssDNA‐specific manner. Proteolytic cleavage of BsSMC is changed upon binding to ATP and ssDNA. The energy‐dependent aggregation of ssDNA might represent a primitive type of chromosome condensation that occurs during segregation of bacterial chromosomes.