title: Characterization of a proteasome alpha-chain from Giardia lamblia.
abstract: To begin to characterize the components of the 20S proteasome of Giardia lamblia, we have cloned a genomic sequence encoding an alpha-chain (type alpha3/C9, predicted size 244 amino acid residues). Southern analysis indicated that a single gene codes for this protein, and a Northern blot exhibited a single signal at 850 nt. An antiserum against a C-terminal fragment of the alpha-chain expressed in Escherichia coli reacted with a single protein band of Mr 27,000 that was present at constant levels in trophozoites and encysting cells. On a 2D blot of the purified 20S proteasome, we identified the cross-reacting component as a single protein of IEP 6.0, in agreement with the IEP predicted by the coding sequence. Our data confirm that the G. lamblia 20S proteasome is typically eukaryotic in containing a set of diverged alpha-subunits.
authors.affiliation: Department of Microbiology, University of Osnabrück, Germany.
authors.forename: V
authors.initials: V
authors.lastname: Emmerlich
authors.forename: H
authors.initials: H
authors.lastname: Scholze
authors.forename: F D
authors.initials: FD
authors.lastname: Gillin
authors.forename: T
authors.initials: T
authors.lastname: Bakker-Grunwald
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015139:Blotting, Southern; D003546:Cysteine Endopeptidases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D016829:Giardia lamblia / Q000201:enzymology / Q000235:genetics*; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D009097:Multienzyme Complexes; D011994:Recombinant Proteins; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex