Characterization of the CDP-2-glycerol biosynthetic pathway in Streptococcus pneumoniae.
Capsule polysaccharide (CPS) plays an important role in the virulence of Streptococcus pneumoniae and is usually used as the pneumococcal vaccine target. Glycerol-2-phosphate is found in the CPS of S. pneumoniae types 15A and 23F and is rarely found in the polysaccharides of other bacteria. The biosynthetic pathway of the nucleotide-activated form of glycerol-2-phosphate (NDP-2-glycerol) has never been identified. In this study, three genes (gtp1, gtp2, and gtp3) from S. pneumoniae 23F that have been proposed to be involved in the synthesis of NDP-2-glycerol were cloned and the enzyme products were expressed, purified, and assayed for their respective activities. Capillary electrophoresis was used to detect novel products from the enzyme-substrate reactions, and the structure of the product was elucidated using electrospray ionization mass spectrometry and nuclear magnetic resonance spectroscopy. Gtp1 was identified as a reductase that catalyzes the conversion of 1,3-dihydroxyacetone to glycerol, Gtp3 was identified as a glycerol-2-phosphotransferase that catalyzes the conversion of glycerol to glycerol-2-phosphate, and Gtp2 was identified as a cytidylyltransferase that transfers CTP to glycerol-2-phosphate to form CDP-2-glycerol as the final product. The kinetic parameters of Gtp1 and Gtp2 were characterized in depth, and the effects of temperature, pH, and cations on these two enzymes were analyzed. This is the first time that the biosynthetic pathway of CDP-2-glycerol has been identified biochemically; this pathway provides a method to enzymatically synthesize this compound.
Wang
Quan
Q
TEDA School of Biological Sciences and Biotechnology, Nankai University, Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, and the Engineering and Research Center for Microbial Functional Genomics and Detection Technology, Ministry of Education,3 Tianjin, China.
Xu
Yanli
Y
Perepelov
Andrei V
AV
Xiong
Wei
W
Wei
Dongmei
D
Shashkov
Alexander S
AS
Knirel
Yuriy A
YA
Feng
Lu
L
Wang
Lei
L
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009702:Nucleoside Diphosphate Sugars / Q000096:biosynthesis*; D021241:Spectrometry, Mass, Electrospray Ionization; D013296:Streptococcus pneumoniae / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D053719:Tandem Mass Spectrometry; D013696:Temperature
D001426:Bacterial Proteins; D009702:Nucleoside Diphosphate Sugars; C100068:cytidine diphosphate glycerol