Cloning and characterization of a LON gene homologue from the human pathogen Paracoccidioides brasiliensis.
A LON gene homologue from the human pathogen Paracoccidioides brasiliensis (PbLON) has been cloned, sequenced and characterized. It encodes a putative ATP-dependent proteinase Lon, which in Saccharomyces cerevisisae (PIM1) is a heat-inducible protein involved in the degradation of abnormal or short-lived proteins in the mitochondria. The PbLON ORF is within a 3369 bp fragment interrupted by two introns located in the 3'segment. The 5' and 3' regions flanking the ORF contain sequences which resemble known transcription elements. Several transcription binding factor motifs have also been found, including sites for heat shock/stress response and nitrogen control. The deduced protein consists of 1063 residues containing a mitochondrial import signal at the N-terminus and conserved ATP-binding (GPPGVGKT) and serine catalytic (KDGPSAG) sites. It shares high identity with Lon homologues from S. cerevisiae (73%), Homo sapiens (62%) and Escherichia coli (56%). In P. brasiliensis, an MDJ1 putative gene has also been partially sequenced adjacent to PbLON, possibly sharing divergently orientated promoter elements. This chromosomal organization is interesting, since Mdj1p is a heat shock chaperone essential for substrate degradation by PIM1 in yeast.
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Departamento de Microbiologia, Imunologia e Parasitologia da Universidade Federal de São Paulo, São Paulo, SP, Brazil.
Puccia
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D049069:ATP-Dependent Proteases; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D002874:Chromosome Mapping; D015825:Chromosomes, Fungal; D003001:Cloning, Molecular; D029968:Escherichia coli Proteins; D005091:Exons; D005800:Genes, Fungal; D050956:HSP40 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000235:genetics*; D007438:Introns; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010228:Paracoccidioides / Q000235:genetics* / Q000472:pathogenicity; D049070:Protease La; D021381:Protein Transport; D029701:Saccharomyces cerevisiae Proteins; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000235:genetics*
D029968:Escherichia coli Proteins; D050956:HSP40 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C087041:MDJ1 protein, S cerevisiae; D008565:Membrane Proteins; D029701:Saccharomyces cerevisiae Proteins; D049069:ATP-Dependent Proteases; D012697:Serine Endopeptidases; C483567:Lon protein, E coli; D049070:Protease La