TY - JOUR

T1 - Two nucleoside transporters in Lactococcus lactis with different substrate specificities

A1 - Martinussen,Jan

A1 - Sørensen,Claus

A1 - Jendresen,Christian Bille

A1 - Kilstrup,Mogens

AU - Martinussen,Jan

AU - Sørensen,Claus

AU - Jendresen,Christian Bille

AU - Kilstrup,Mogens

PB - Society for General Microbiology

PY - 2010

Y1 - 2010

N2 - In an alternative to biosynthesis of nucleotides, most organisms are capable of exploiting exogenous nucleotide sources. In order to do so, the nucleotide precursors must pass the membrane, which requires the presence of transporters. Normally, phosphorylated compounds are not subject to transport, and the utilization of nucleotides is dependent on exogenous phosphatases. The composition of transporters with specificity for purine and pyrimidine nucleosides and nucleobases is subject to variation. The ability of Lactococcus lactis to transport different nucleosides across the cell membrane was characterized at both genetic and physiological level, using mutagenesis and by measuring the growth and uptake of nucleosides in the different mutants supplemented with different nucleosides. Two high affinity transporters were identified: BmpA-NupABC was shown to be an ABC transporter with the ability to actively transport all common nucleosides, whereas UriP was shown to be responsible for the uptake of only uridine and deoxyuridine. Interestingly, the four genes encoding the ABC transporter were found at different positions on the chromosome. The bmpA gene was separated from the nupABC operon by 60 kb. Moreover, bmpA was subject to regulation by purine availability, whereas the nupABC operon was constitutively expressed.

AB - In an alternative to biosynthesis of nucleotides, most organisms are capable of exploiting exogenous nucleotide sources. In order to do so, the nucleotide precursors must pass the membrane, which requires the presence of transporters. Normally, phosphorylated compounds are not subject to transport, and the utilization of nucleotides is dependent on exogenous phosphatases. The composition of transporters with specificity for purine and pyrimidine nucleosides and nucleobases is subject to variation. The ability of Lactococcus lactis to transport different nucleosides across the cell membrane was characterized at both genetic and physiological level, using mutagenesis and by measuring the growth and uptake of nucleosides in the different mutants supplemented with different nucleosides. Two high affinity transporters were identified: BmpA-NupABC was shown to be an ABC transporter with the ability to actively transport all common nucleosides, whereas UriP was shown to be responsible for the uptake of only uridine and deoxyuridine. Interestingly, the four genes encoding the ABC transporter were found at different positions on the chromosome. The bmpA gene was separated from the nupABC operon by 60 kb. Moreover, bmpA was subject to regulation by purine availability, whereas the nupABC operon was constitutively expressed.

UR - http://mic.sgmjournals.org/cgi/reprint/156/10/3148

U2 - 10.1099/mic.0.039818-0

DO - 10.1099/mic.0.039818-0

JO - Microbiology

JF - Microbiology

SN - 1350-0872

VL - 156

SP - 3148

EP - 3157

ER -