CspD, a novel DNA replication inhibitor induced during the stationary phase in Escherichia coli.
CspD is a stationary phase-induced, stress response protein in the CspA family of Escherichia coli. Here, we demonstrate that overproduction of CspD is lethal, with the cells displaying a morphology typical of cells with impaired DNA replication. CspD consists mainly of beta-strands, and the purified protein exists exclusively as a dimer and binds to single-stranded (ss)DNA and RNA in a dose-dependent manner without apparent sequence specificity. CsdD effectively inhibits both the initiation and the elongation steps of minichromosome replication in vitro. Electron microscopic studies revealed that CspD tightly packs ssDNA, resulting in structures distinctly different from those of SSB-coated DNA. We propose that CspD dimers, with two independent beta-sheets interacting with ssDNA, function as a novel inhibitor of DNA replication and play a regulatory role in chromosomal replication in nutrient-depleted cells.
Department of Biochemistry, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
K
K
Yamanaka
W
W
Zheng
E
E
Crooke
Y H
YH
Wang
M
M
Inouye
D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D001483:Base Sequence; D002455:Cell Division / Q000235:genetics; D004247:DNA / Q000378:metabolism; D004261:DNA Replication / Q000235:genetics*; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019281:Dimerization; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development*; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009154:Mutation; D051738:Origin Recognition Complex; D012329:RNA, Bacterial / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics
D001426:Bacterial Proteins; C088098:CspD protein, bacteria; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; C114650:OriC chromosomal replication origin; D051738:Origin Recognition Complex; D012329:RNA, Bacterial; D014764:Viral Proteins; C490240:cspH protein, E coli; D004247:DNA