Isolation of purine auxotrophic mutants of Lactococcus lactis and characterization of the gene hpt encoding hypoxanthine guanine phosphoribosyltransferase.
Five purine auxotrophic mutants of Lactococcus lactis were isolated. L. lactis was capable of converting adenine, guanine and hypoxanthine to AMP, GMP and IMP, respectively, indicating the existence of adenine phosphoribosyltransferase (APRT) and hypoxanthine guanine phosphoribosyltransferase (HGPRT) activities. A 1.3 kb DNA fragment from L. lactis was cloned by complementation of the hpt mutation in Escherichia coli. Introduction of this fragment into L. lactis resulted in an increase in HGPRT activity. In vitro transcription and translation analysis showed that the fragment coded for a polypeptide with M(r) of 22,000. The nucleotide sequence of this hpt gene was determined.
Nilsson
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Department of Genetics, Chr. Hansen's Laboratorium Denmark A/S, Hørsholm, Denmark.
Lauridsen
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AA
D000228:Adenine Phosphoribosyltransferase / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics* / Q000378:metabolism; D013294:Lactococcus lactis / Q000201:enzymology* / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids; D014176:Protein Biosynthesis; D011687:Purines / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D004269:DNA, Bacterial; D011687:Purines; D011994:Recombinant Proteins; D000228:Adenine Phosphoribosyltransferase; D007041:Hypoxanthine Phosphoribosyltransferase