Properties of the Glucose-6-Phosphate Transporter from Chlamydia pneumoniae (HPTcp) and the Glucose-6-Phosphate Sensor from Escherichia coli (UhpC)

ABSTRACT The amino acid sequence of the proposed glucose-6-phosphate (Glc6P) transporter from Chlamydia pneumoniae (HPTcp; hexose phosphate transporter [Chlamydia pneumoniae]) exhibits a higher degree of similarity to the Escherichia coli Glc6P sensor (UhpC) than to the E. coli Glc6P transporter (UhpT). Overexpression of His-UhpC in a UhpT-deficient E. coli strain revealed that the sensor protein is also able to transport Glc6P and exhibits an apparent Km (Glc6P) of 25 μM, whereas His-HPTcp exhibits an apparent Km (Glc6P) of 98 μM. His-HPTcp showed a four-times-lower specific activity than His-UhpT but a 56-times-higher specific activity than His-UhpC. Like His-UhpT and His-UhpC, the carrier His-HPTcp performs a sugar-phosphate/inorganic-phosphate antiporter mode of transport. Surprisingly, while physiological concentrations of inorganic phosphate competitively inhibited transport mediated by the E. coli proteins His-UhpT and His-UhpC, transport mediated by His-HPTcp was not inhibited. Interestingly, C3-organophosphates stimulated His-HPTcp activity but not His-UhpT- or His-UhpC-catalyzed Glc6P transport. In contrast to His-UhpC, the His-HPTcp protein does not act as a Glc6P sensor in the uhp regulon.

[1]  P. Maloney,et al.  Transmembrane Segment 11 of UhpT, the Sugar Phosphate Carrier ofEscherichia coli, Is an α-Helix That Carries Determinants of Substrate Selectivity* , 2001, The Journal of Biological Chemistry.

[2]  R. Kadner,et al.  The Phosphoryl Transfer Domain of UhpB Interacts with the Response Regulator UhpA , 2001, Journal of bacteriology.

[3]  J. Sambrook,et al.  Molecular Cloning: A Laboratory Manual , 2001 .

[4]  Marie-Claire Mchin,et al.  Glucose-6-phosphate transporter and receptor functions of the glucose 6-phosphatase system analyzed from a consensus defined by multiple alignments. , 2000 .

[5]  E. Iliffe-Lee,et al.  Regulation of carbon metabolism in Chlamydia trachomatis , 2000, Molecular microbiology.

[6]  P. Maloney,et al.  Altered Substrate Selectivity in a Mutant of an Intrahelical Salt Bridge in UhpT, the Sugar Phosphate Carrier of Escherichia coli * , 1999, The Journal of Biological Chemistry.

[7]  H. Winkler,et al.  Two Nucleotide Transport Proteins in Chlamydia trachomatis, One for Net Nucleoside Triphosphate Uptake and the Other for Transport of Energy , 1999, Journal of bacteriology.

[8]  H. Winkler,et al.  Membrane topology of the Rickettsia prowazekii ATP/ADP translocase revealed by novel dual pho-lac reporters. , 1999, Journal of molecular biology.

[9]  P. Maloney,et al.  Functional Symmetry of UhpT, the Sugar Phosphate Transporter ofEscherichia coli * , 1998, The Journal of Biological Chemistry.

[10]  R. W. Davis,et al.  Genome sequence of an obligate intracellular pathogen of humans: Chlamydia trachomatis. , 1998, Science.

[11]  C. Sevier,et al.  Identification of Two Essential Arginine Residues in UhpT, the Sugar Phosphate Antiporter of Escherichia coli , 1998, The Journal of Membrane Biology.

[12]  I. Gérin,et al.  Sequence of a putative glucose 6‐phosphate translocase, mutated in glycogen storage disease type Ib 1 , 1997, FEBS letters.

[13]  G. McClarty,et al.  The obligate intracellular bacterium Chlamydia trachomatis is auxotrophic for three of the four ribonucleoside triphosphates , 1993, Molecular microbiology.

[14]  R. Kadner,et al.  Structure and function of the uhp genes for the sugar phosphate transport system in Escherichia coli and Salmonella typhimurium , 1992, Journal of bacteriology.

[15]  J. Moulder.  Interaction of chlamydiae and host cells in vitro. , 1991, Microbiological reviews.

[16]  P. Maloney,et al.  The mechanism of glucose 6-phosphate transport by Escherichia coli. , 1988, The Journal of biological chemistry.

[17]  P. Maloney,et al.  Characterization of phosphate:hexose 6-phosphate antiport in membrane vesicles of Streptococcus lactis. , 1984, The Journal of biological chemistry.

[18]  P. Maloney,et al.  Phosphate/hexose 6-phosphate antiport in Streptococcus lactis , 1984, Journal of bacteriology.

[19]  T. Hatch,et al.  Adenine nucleotide and lysine transport in Chlamydia psittaci , 1982, Journal of bacteriology.

[20]  M. M. Bradford.  A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. , 1976, Analytical biochemistry.

[21]  T. Hatch.  Utilization of L-cell nucleoside triphosphates by Chlamydia psittaci for ribonucleic acid synthesis , 1975, Journal of bacteriology.

[22]  H. Winkler.  Distribution of an Inducible Hexose-Phosphate Transport System Among Various Bacteria , 1973, Journal of bacteriology.

[23]  W. Arber,et al.  Transduction of chromosomal genes and episomes in Escherichia coli. , 1960, Virology.

[24]  W. Arber.  Polylysogeny for Bacteriophage Lambda. , 1960 .

[25]  M. Méchin,et al.  Glucose‐6‐phosphate transporter and receptor functions of the glucose 6‐phosphatase system analyzed from a consensus defined by multiple alignments , 2000, Proteins.

[26]  R. Kadner,et al.  A transmembrane signalling complex controls transcription of the Uhp sugar phosphate transport system. , 1994, Research in microbiology.

[27]  M. Saier,et al.  A major superfamily of transmembrane facilitators that catalyse uniport, symport and antiport. , 1993, Trends in biochemical sciences.

[28]  G. W. Dietz.  The hexose phosphate transport system of Escherichia coli. , 1976, Advances in enzymology and related areas of molecular biology.

[29]  J. Moulder.  The Biochemistry of Intracellular Parasitism , 1962 .