PGPB Antibody – Rabbit Polyclonal

The pgpB gene is nonessential, but is synthetically lethal with a bacA ybjG double mutant, due to its UppP activity. ybjG, pgpB, and lpxT are paralogs. [More information is available at EcoGene: EG10705]. PgpB is one of three phosphatidylglycerophosphatase (PGP-ase) activities in Escherichia coli. [More information is available at EcoCyc: EG10705].

Function: Catalyzes the dephosphorylation of diacylglycerol diphosphate (DGPP) to phosphatidate (PA) and the subsequent dephosphorylation of PA to diacylglycerol (DAG). Also has undecaprenyl pyrophosphate phosphatase activity, required for the biosynthesis of the lipid carrier undecaprenyl phosphate. Can also use lysophosphatidic acid (LPA) and phosphatidylglycerophosphate as substrates. The pattern of activities varies according to subcellular location, PGP phosphatase activity is higher in the cytoplasmic membrane, whereas PA and LPA phosphatase activities are higher in the outer membrane. Activity is independent of a divalent cation ion and insensitive to inhibition by N-ethylmaleimide. Ref.5 Ref.6 Ref.8 Ref.9

Catalytic activity: Phosphatidylglycerophosphate + H2O = phosphatidylglycerol + phosphate. Ref.5 Ref.81,2-diacyl-sn-glycerol 3-diphosphate + H2O = 1,2-diacyl-sn-glycerol 3-phosphate + phosphate. Ref.5 Ref.8A 1,2-diacylglycerol 3-phosphate + H2O = a 1,2-diacyl-sn-glycerol + phosphate. Ref.5 Ref.8Ditrans,octacis-undecaprenyl diphosphate + H2O = ditrans,octacis-undecaprenyl phosphate + phosphate. Ref.5 Ref.8

Enzyme regulation: Inhibited by Mn2+ ions.

Pathway: Phospholipid metabolism; phosphatidylglycerol biosynthesis; phosphatidylglycerol from CDP-diacylglycerol: step 2/2.

Subcellular location: Cell inner membrane; Multi-pass membrane protein. Cell outer membrane; Multi-pass membrane protein Ref.1 Ref.7.

Post-translational modification: The N-terminus is blocked.

Sequence similarities: Belongs to the PA-phosphatase related phosphoesterase family.

Biophysicochemical propertiesKinetic parameters:KM=530 µM for undecaprenyl pyrophosphate Ref.5 Ref.8KM=96 µM for farnesyl pyrophosphateKM=80 µM for diacylglycerol pyrophosphateKM=1700 µM for phosphatidateVmax=2167 nmol/min/mg enzyme with diacylglycerol pyrophosphate as substrateVmax=313 nmol/min/mg enzyme with phosphatidate as substratepH dependence:Optimum pH is 6.5 for DGPP phosphatase activity and 6.5-7.5 for undecaprenyl pyrophosphate phosphatase activity.

Mass spectrometry: Molecular mass is 30151 Da from positions 2 - 254. Determined by MALDI. Reported mass includes mass of a C-terminal His6 tag. Ref.8