Stereochemical course of the reactions catalyzed by the bacterial phosphoenolpyruvate:mannitol phosphotransferase system.
We have determined the overall stereochemical course of the reactions leading to the phosphorylation of D-mannitol by mannitol-specific enzyme II (EIIMtl) of the Escherichia coli phosphoenolpyruvate- (PEP) dependent phosphotransferase system (PTS). In the presence of enzyme I and HPr of the PTS, and of membranes containing EIIMtl, the phospho group from [(R)-16O,17O,18O]PEP was transferred to D-mannitol to form mannitol 1-phosphate with overall inversion of the configuration at phosphorus with respect to that of PEP. Since in the course of these reactions enzyme I and HPr are each covalently phosphorylated at a single site and inversion of the chiral phospho group from PEP indicates an odd number of transfer steps overall, transfer from phospho-HPr to mannitol via EIIMtl must also occur in an odd number of steps. Taken together with the fact that catalytically important phospho-EIIMtl intermediates have been demonstrated biochemically, our results imply that EIIMtl is sequentially phosphorylated at two different sites during phospho transfer from phospho-HPr to mannitol. This conclusion is consistent with the available evidence on phospho-EIIMtl intermediates and in particular with the recent report that two different phospho peptides can be isolated from the fully phosphorylated protein [Pas, H. H., & Robillard, G. T. (1988) Biochemistry 27, 5835-5839].
Mueller
E G
EG
Department of Chemistry, Harvard University, Cambridge, Massachusetts 02138.
Khandekar
S S
SS
Knowles
J R
JR
Jacobson
G R
GR
D001665:Binding Sites; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins; D005988:Glyceric Acids / Q000378:metabolism; D008353:Mannitol / Q000378:metabolism; D009004:Monosaccharide Transport Proteins; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000378:metabolism*; D010766:Phosphorylation; D012486:Salmonella typhimurium / Q000378:metabolism; D013237:Stereoisomerism
D029968:Escherichia coli Proteins; D005988:Glyceric Acids; D009004:Monosaccharide Transport Proteins; C008885:2-phosphoglycerate; D008353:Mannitol; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C022358:mannitol PTS permease, E coli