Figure 3.
Interaction of guanine nucleotides with EF-Tu D109A in the absence of EF-Ts. (A) Time courses of mant-GTP (1 μM, line 1) or mant-GDP (1 μM, line 2) binding to nucleotide-free EF-Tu D109A (0.25 μM) measured by fluorescence resonance energy transfer between the single tryptophan in EF-Tu and the mant group (line 3 control without EF-Tu). (B) Concentration dependence of kapp. kapp-values were calculated by single-exponential fitting from time courses in panel A. Circles: mant-GDP; triangles: mant-GTP.