Limits...
Large-scale filament formation inhibits the activity of CTP synthetase.

Barry RM, Bitbol AF, Lorestani A, Charles EJ, Habrian CH, Hansen JM, Li HJ, Baldwin EP, Wingreen NS, Kollman JM, Gitai Z - Elife (2014)

Bottom Line: Structure-guided mutagenesis and mathematical modeling further indicate that coupling activity to polymerization promotes cooperative catalytic regulation.This previously uncharacterized regulatory mechanism is important for cellular function since a mutant that disrupts CtpS polymerization disrupts E. coli growth and metabolic regulation without reducing CTP levels.We propose that regulation by large-scale polymerization enables ultrasensitive control of enzymatic activity while storing an enzyme subpopulation in a conformationally restricted form that is readily activatable.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology, Princeton University, Princeton, United States.

Show MeSH

Related in: MedlinePlus

CtpS activity is not sensitive to incubation on ice.Due to concerns that placing resuspended polymers on ice may affect enzymatic activity significantly, we compared the activity level of CtpS reactions under typical conditions (t = 0 min) vs incubation on ice. For later time points, 10 µl of cold CtpS-containing buffer was added to room temperature activity buffer to match the conditions of the ultracentrifuguation assay (Figure 1C). Overall activity does not change over the course of the experiment at the lower temperature.DOI:http://dx.doi.org/10.7554/eLife.03638.007
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4126345&req=5

fig1s4: CtpS activity is not sensitive to incubation on ice.Due to concerns that placing resuspended polymers on ice may affect enzymatic activity significantly, we compared the activity level of CtpS reactions under typical conditions (t = 0 min) vs incubation on ice. For later time points, 10 µl of cold CtpS-containing buffer was added to room temperature activity buffer to match the conditions of the ultracentrifuguation assay (Figure 1C). Overall activity does not change over the course of the experiment at the lower temperature.DOI:http://dx.doi.org/10.7554/eLife.03638.007

Mentions: D) We have demonstrated CtpS disassembly in the experiment of Figure 1C by including a supplemental figure showing the corresponding light scattering change over time (Figure 1–figure supplement 4).


Large-scale filament formation inhibits the activity of CTP synthetase.

Barry RM, Bitbol AF, Lorestani A, Charles EJ, Habrian CH, Hansen JM, Li HJ, Baldwin EP, Wingreen NS, Kollman JM, Gitai Z - Elife (2014)

CtpS activity is not sensitive to incubation on ice.Due to concerns that placing resuspended polymers on ice may affect enzymatic activity significantly, we compared the activity level of CtpS reactions under typical conditions (t = 0 min) vs incubation on ice. For later time points, 10 µl of cold CtpS-containing buffer was added to room temperature activity buffer to match the conditions of the ultracentrifuguation assay (Figure 1C). Overall activity does not change over the course of the experiment at the lower temperature.DOI:http://dx.doi.org/10.7554/eLife.03638.007
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4126345&req=5

fig1s4: CtpS activity is not sensitive to incubation on ice.Due to concerns that placing resuspended polymers on ice may affect enzymatic activity significantly, we compared the activity level of CtpS reactions under typical conditions (t = 0 min) vs incubation on ice. For later time points, 10 µl of cold CtpS-containing buffer was added to room temperature activity buffer to match the conditions of the ultracentrifuguation assay (Figure 1C). Overall activity does not change over the course of the experiment at the lower temperature.DOI:http://dx.doi.org/10.7554/eLife.03638.007
Mentions: D) We have demonstrated CtpS disassembly in the experiment of Figure 1C by including a supplemental figure showing the corresponding light scattering change over time (Figure 1–figure supplement 4).

Bottom Line: Structure-guided mutagenesis and mathematical modeling further indicate that coupling activity to polymerization promotes cooperative catalytic regulation.This previously uncharacterized regulatory mechanism is important for cellular function since a mutant that disrupts CtpS polymerization disrupts E. coli growth and metabolic regulation without reducing CTP levels.We propose that regulation by large-scale polymerization enables ultrasensitive control of enzymatic activity while storing an enzyme subpopulation in a conformationally restricted form that is readily activatable.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology, Princeton University, Princeton, United States.

Show MeSH
Related in: MedlinePlus