Open AccessThe Bacillus subtilis HBsu Protein Modifies the Effects of α/β-Type, Small Acid-Soluble Spore Proteins on DNA
Author(s) -
Margery A. Ross,
Peter Setlow
Publication year - 2000
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.182.7.1942-1948.2000
Subject(s) - bacillus subtilis , biology , dna supercoil , dna , spore , nucleoid , dna gyrase , microbiology and biotechnology , escherichia coli , puc19 , endospore , bacteria , biochemistry , plasmid , genetics , dna replication , gene
HBsu, theBacillus subtilis homolog of theEscherichia coli HU proteins and the major chromosomal protein in vegetative cells ofB. subtilis , is present at similar levels in vegetative cells and spores (∼5 × 104 monomers/genome). The level of HBsu in spores was unaffected by the presence or absence of the α/β-type, small acid-soluble proteins (SASP), which are the major chromosomal proteins in spores. In developing forespores, HBsu colocalized with α/β-type SASP on the nucleoid, suggesting that HBsu could modulate α/β-type SASP-mediated properties of spore DNA. Indeed, in vitro studies showed that HBsu altered α/β-type SASP protection of pUC19 from DNase digestion, induced negative DNA supercoiling opposing α/β-type SASP-mediated positive supercoiling, and greatly ameliorated the α/β-type SASP-mediated increase in DNA persistence length. However, HBsu did not significantly interfere with the α/β-type SASP-mediated changes in the UV photochemistry of DNA that explain the heightened resistance of spores to UV radiation. These data strongly support a role for HBsu in modulating the effects of α/β-type SASP on the properties of DNA in the developing and dormant spore.