title: Overproduction, purification and characterisation of Tbj1, a novel Type III Hsp40 from Trypanosoma brucei, the African sleeping sickness parasite.
abstract: The heat shock protein 40 (Hsp40) family of proteins act as co-chaperones of the heat shock protein 70 (Hsp70) chaperone family, and together they play a vital role in the maintenance of cellular homeostasis. The Type III class of Hsp40s are diverse in terms of both sequence identity and function and have not been extensively characterised. The Trypanosoma brucei parasite is the causative agent of Human African Trypanosomiasis, and possesses an unusually large Hsp40 complement, consisting mostly of Type III Hsp40s. A novel T. brucei Type III Hsp40, Tbj1, was heterologously expressed, purified, and found to exist as a compact monomer in solution. Using polyclonal antibodies to the full-length recombinant protein, Tbj1 was found by Western analysis to be expressed in the T. brucei bloodstream-form. Tbj1 was found to be able to assist two different Hsp70 proteins in the suppression of protein aggregation in vitro, despite being unable to stimulate their ATPase activity. This indicated that while Tbj1 did not possess independent chaperone activity, it potentially functioned as a novel co-chaperone of Hsp70 in T. brucei.
authors.affiliation: Biomedical Biotechnology Research Unit, Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, Grahamstown 6140, South Africa.
authors.forename: Cassandra A
authors.initials: CA
authors.lastname: Louw
authors.forename: Michael H
authors.initials: MH
authors.lastname: Ludewig
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Blatch
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D050956:HSP40 Heat-Shock Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017510:Protein Folding; D015800:Protozoan Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014346:Trypanosoma brucei brucei / Q000235:genetics / Q000378:metabolism*; D014353:Trypanosomiasis, African / Q000382:microbiology*
chemical_list: D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D018832:Molecular Chaperones; D015800:Protozoan Proteins; D011994:Recombinant Proteins