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. Author manuscript; available in PMC: 2011 Dec 1.
Published in final edited form as: Mol Microbiol. 2010 Oct 12;78(5):1313–1323. doi: 10.1111/j.1365-2958.2010.07408.x

Table 2.

Parameters from fits of kinase activity as a function of aspartate concentration a

Modifications [Asp]½ μM Fold Kinase Activation Hill Coefficient
0 (EEEE) 0.3 ± 0.2 0.7 ± 0.5 1.5 ± 0.4
1 (QEEE) 0.5 ± 0.1 88 ± 8.0 2.5 ± 0.3
2 (QEQE) 2.7 ± 0.5 102 ± 9.6 2.5 ± 0.1
3 (QEQQ) 11.1 ± 1.7 113 ± 4.4 2.2 ± 0.1
4 (QQQQ) 45.9 ± 2.5 133 ± 2.4 1.4 ± 0.4
a

Data shown in Fig 6A were fit to the relationship p = pu + (ps [Asp]n)/([Asp]½ n + [Asp]n) where p is the rate of phosphorylation at a given aspartate concentration, pu is the rate in the absence of aspartate, ps is the rate at saturating aspartate, [Asp]½ is the aspartate concentration at which stimulation of the initial rate is half maximum and n is the Hill coefficient. Fold Kinase Activation is (pu − pA)/pA where pA is the rate of phosphorylation of CheA in the absence of chemoreceptors and CheW. The table shows mean values and standard deviations for these parameters derived from fits for at least three independent experiments determining kinase activity for Tar with 0 to 4 adaptational modifications in the presence of CheA and CheW in conditions that form signaling complexes.