Characterization of a chaperone ClpB homologue of Paracoccidioides brasiliensis

We report the cloning and sequence analysis of a genomic clone encoding a Paracoccidioides brasiliensis ClpB chaperone homologue (PbClpB). The clpb gene was identified in a lambda Dash II library. Sequencing of Pbclpb revealed a long open reading frame capable of encoding a 792 amino acid, 87.9 kDa protein, pI of 5.34. The predicted polypeptide contains several consensus motifs of the ClpB proteins. Canonical sequences such as two putative nucleotide-binding sites, chaperonins ClpA/B signatures and highly conserved casein kinase phosphorylation domains are present. ClpB is 69% to 49% identical to members of the ClpB family from several organisms from prokaryotes to eukaryotes. The transcript of PbclpB was detected as a mRNA species of 3.0 kb, preferentially expressed in the yeast parasitic phase of the fungus. A 89 kDa protein was also detected in yeast cells of P. brasiliensis.