Cloning of a Candida albicans peptide transport gene.
A Candida albicans peptide transport gene, CaPTR2, was cloned from a C. albicans genomic library by functional complementation of a peptide transport deficient mutant (strain ptr2-2) of Saccharomyces cerevisiae. CaPTR2 restored peptide transport to transformants as determined by uptake of radiolabelled dileucine, growth on dipeptides as sources of required amino acids, and restoration of growth inhibition by toxic peptides. Plasmid curing experiments demonstrated that the peptide transport phenotype was plasmid borne. CaPTR2 was localized to chromosome R of C. albicans by contour-clamped homologous electric field gel chromosome blots. Deletion subclones and frameshift mutagenesis were used to narrow the peptide transport complementing region to a 5.1 kb DNA fragment. DNA sequencing of the complementing region identified an ORF of 1869 bp containing an 84 nucleotide intron. The deduced amino acid sequence predicts a protein of 70 kDa consisting of 623 amino acids with 12 hydrophobic segments. A high level of identity was found between the predicted protein and peptide transport proteins of S. cerevisiae and Arabidopsis thaliana. This study represents the first steps in the genetic characterization of peptide transport in C. albicans and initiates a molecular approach for the study of drug delivery against this pathogen.
Basrai
Munira A
MA
Department of Microbiology and Program in Cellular, Molecular, and Developmental Biology, University of Tennessee, Knoxville, TN 37996-0845, USA.
Lubkowitz
Mark A
MA
Department of Microbiology and Program in Cellular, Molecular, and Developmental Biology, University of Tennessee, Knoxville, TN 37996-0845, USA.
Perry
Jack R
JR
Department of Microbiology and Program in Cellular, Molecular, and Developmental Biology, University of Tennessee, Knoxville, TN 37996-0845, USA.
Miller
David
D
Department of Microbiology and Program in Cellular, Molecular, and Developmental Biology, University of Tennessee, Knoxville, TN 37996-0845, USA.
Krainer
Eduardo
E
Department of Chemistry, College of Staten Island, City University of New York, Staten Island, New York 10301, USA.
Naider
Fred
F
Department of Chemistry, College of Staten Island, City University of New York, Staten Island, New York 10301, USA.
Becker
Jeffrey M
JM
Department of Microbiology and Program in Cellular, Molecular, and Developmental Biology, University of Tennessee, Knoxville, TN 37996-0845, USA.
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism; D001483:Base Sequence; D001692:Biological Transport; D002176:Candida albicans / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000378:metabolism; D005656:Fungal Proteins / Q000096:biosynthesis* / Q000235:genetics; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D015698:Genomic Library; D007700:Kinetics; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D000596:Amino Acids; D002352:Carrier Proteins; D004271:DNA, Fungal; D005656:Fungal Proteins; D026901:Membrane Transport Proteins; C094019:PRT2 protein, Candida albicans; D010455:Peptides