Disease relevance of clpB

• The gene clpB encoding an analog of ClpA had been found at 57 min on the E. coli chromosome [1].
• Characterization of Brucella suis clpB and clpAB mutants and participation of the genes in stress responses [2].
• Using a PCR-based genomic walking method, the nucleotide sequence of a clpB homolog from Campylobacter jejuni was determined [3].

High impact information on clpB

• By polymerase chain reaction-aided site-directed mutagenesis, both the proteins have been shown to be encoded by the same reading frame of the clpB gene, the 93-kDa protein (ClpB93) from the 5'-end AUG translational initiation site and the 79-kDa protein (ClpB79) from the 149th codon (an internal GUG start site) [4].
• Nucleotide sequence analysis of the clp operon, encoding the biosynthesis of CS31A, revealed the presence of a regulatory gene, clpB [5].
• Although a low-copy plasmid carrying clpB93 could rescue the sensitivity of a clpB-null mutant cell at 52 degreesC, none of the plasmids carrying the mutations in the ATP-binding sites could [6].
• We found that although overexpressed ClpB95 or ClpB80 can independently restore basal thermotolerance to DeltaclpB cells, strains expressing ClpB80 from the clpB chromosomal locus do not exhibit increased resistance to thermal killing at 50 degrees C relative to clpB null cells [7].
• Simultaneous inactivation of clpA and clpB resulted in a mutant that was sensitive to oxidative stress [2].

Biological context of clpB

• 1. The F84.1 protein was overproduced in strains containing the clpB gene on a plasmid and was absent from two-dimensional gels from a clpB null mutation [8].
• Within the clpB promoter region, as indicated by primer extension analysis, we identified a sequence identical to the E. coli sigma70 consensus promoter [3].
• In the attempt to characterize the stress response in Brucella suis, a gene highly homologous to Escherichia coli clpB was isolated from Brucella suis, and the deduced amino acid sequence showed features typical of the ClpB ATPase family of stress response proteins [2].

Associations of clpB with chemical compounds

• Under high-temperature stress conditions, ClpB of B. suis was induced, and an isogenic B. suis clpB mutant showed increased sensitivity to high temperature, but also to ethanol stress and acid pH [2].

Other interactions of clpB

• Chromosomal clpB transcripts also increased upon temperature upshift and were totally absent in the rpoH deletion strain [1].
• Deletion of the heat shock genes clpB and htpG resulted in growth defects at 42 degrees C when combined with the dnaK756 or groES30 alleles, while the Deltaibp mutation had a detrimental effect only on the growth of dnaK756 mutants [9].
• Northern blot analysis confirmed that clpB is heat-inducible in C. jejuni [3].

Analytical, diagnostic and therapeutic context of clpB

• Site-directed mutagenesis of the dual translational initiation sites of the clpB gene of Escherichia coli and characterization of its gene products [4].
• The clpB gene product has been purified to near homogeneity by DEAE-Sepharose and heparin-agarose column chromatographies [10].
• In the detection assay, a heat shock was applied to the cells prior to disruption to induce the synthesis of clpB mRNA and the mRNA was extracted, purified, and finally amplified using NASBA [11].

References