title: Mycobacterium tuberculosis expresses two chaperonin-60 homologs.
abstract: A 65-kDa protein and a 10-kDa protein are two of the more strongly immunoreactive components of Mycobacterium tuberculosis, the causative agent of tuberculosis. The 65-kDa antigen has homology with members of the GroEL or chaperonin-60 (Cpn60) family of heat shock proteins. The 10-kDa antigen has homology with the GroES or chaperonin-10 family of heat shock proteins. These two proteins are encoded by separate genes in M. tuberculosis. The studies reported here reveal that M. tuberculosis contains a second Cpn60 homolog located 98 bp downstream of the 10-kDa antigen gene. The second Cpn60 homolog (Cpn60-1) displays 61% amino acid sequence identity with the 65-kDa antigen (Cpn60-2) and 53% and 41% identity with the Escherichia coli GroEL protein and the human P60 protein, respectively. Primer-extension analysis revealed that transcription starts 29 bp upstream of the translation start of the Cpn60-1 homolog and protein purification studies indicate that the cpn60-1 gene is expressed as an approximately 60-kDa polypeptide.
authors.affiliation: Department of Medical Microbiology, St. George's Hospital Medical School, London, United Kingdom.
authors.forename: T H
authors.initials: TH
authors.lastname: Kong
authors.forename: A R
authors.initials: AR
authors.lastname: Coates
authors.forename: P D
authors.initials: PD
authors.lastname: Butcher
authors.forename: C J
authors.initials: CJ
authors.lastname: Hickman
authors.forename: T M
authors.initials: TM
authors.lastname: Shinnick
mesh_terms: D000942:Antigens, Bacterial / Q000096:biosynthesis / Q000235:genetics*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D018834:Chaperonin 60; D002846:Chromatography, Affinity; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D015723:Gene Library; D005798:Genes, Bacterial; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009163:Mycobacterium bovis / Q000235:genetics; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000378:metabolism; D009838:Oligodeoxyribonucleotides; D012329:RNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D018834:Chaperonin 60; D004269:DNA, Bacterial; D006360:Heat-Shock Proteins; D009838:Oligodeoxyribonucleotides; D012329:RNA, Bacterial