Rate and equilibrium constants for phosphoryltransfer between active site histidines of Escherichia coli HPr and the signal transducing protein IIIGlc.

The Journal of Biological Chemistry
N D Meadow, S Roseman

Abstract

The bacterial phosphoenolpyruvate:glycose phosphotransferase system (PTS) plays a central role in catabolizing many sugars; regulation is effected by phosphorylation of PTS proteins. In Escherichia coli, the phosphoryltransfer sequence for glucose uptake is: PEP --> Enzyme I(His191) --> HPr(His15) --> IIIGlc(His90) --> IIGlc(Cys421) --> glucose. A rapid quench method has now been developed for determining the rate and equilibrium constants of these reactions. The method was validated by control experiments, and gave the following results for phosphoryltransfer between the following protein pairs. For phospho-HPr/IIIGlc (and HPr/phospho-IIIGlc), k1 = 6.1 x 10(7) M-1 s-1, k-1 = 4.7 x 10(7); for the mutant H75QIIIGlc in place of IIIGlc, k1 = 2.8 x 10(5) M-1 s-1, k-1 = 2.3 x 10(5). The derived Keq values agreed with the Keq obtained without use of the rapid quench apparatus. Keq for both reactions is 1-1.5. The rate of phosphoryltransfer between HPr and wild type IIIGlc is close to a diffusion-controlled process, while the reactions involving the mutant H75QIIIGlc are 200-fold slower. These rate differences are explained by an hypothesis for the mechanism of phosphoryltransfer between HPr and IIIGlc based on the structures of mutan...Continue Reading

References

Jun 1, 1976·Analytical Biochemistry·J P FroehlichR L Berger
May 1, 1979·Analytical Biochemistry·E B WaygoodS Roseman
Jan 1, 1990·Annual Review of Biochemistry·N D MeadowS Roseman
Jun 1, 1989·Proceedings of the National Academy of Sciences of the United States of America·K A PresperS Roseman
Jan 1, 1987·Methods in Enzymology·T A KunkelR A Zakour
Jan 1, 1983·Canadian Journal of Biochemistry and Cell Biology = Revue Canadienne De Biochimie Et Biologie Cellulaire·R L Mattoo, E B Waygood
Sep 1, 1994·Molecular Microbiology·M H Saier, J Reizer
Sep 1, 1993·Microbiological Reviews·P W PostmaG R Jacobson
Oct 1, 1964·Proceedings of the National Academy of Sciences of the United States of America·W KUNDIGS ROSEMAN

❮ Previous
Next ❯

Citations

Dec 13, 2006·Microbiology and Molecular Biology Reviews : MMBR·Josef DeutscherPieter W Postma
Aug 25, 2016·PLoS Biology·Rahul SomavanshiVictor Sourjik
Mar 21, 2006·The Journal of Biological Chemistry·Himatkumar V PatelSaul Roseman

❮ Previous
Next ❯

Related Concepts

Related Feeds

ASBMB Publications

The American Society for Biochemistry and Molecular Biology (ASBMB) includes the Journal of Biological Chemistry, Molecular & Cellular Proteomics, and the Journal of Lipid Research. Discover the latest research from ASBMB here.