Fig. 4

Recombinant HvExoI recognises β-d-Glc in the ⁴C₁ conformation. a ¹H STD NMR spectrum (top) and reference spectrum (below), acquired with recombinant HvExoI and Glc (40 µM and 2.4 mM, respectively) at 600 MHz and 283 K. Only protons of β-d-Glc (squares) showed STDs. Off and on resonance frequencies were set at 100 ppm and 0.65 ppm, respectively. The Gaussian shaped pulse (30 ms) was used for selective irradiation with total saturation time of 2 s. b trNOESY spectrum of recombinant HvExoI and Glc (57 µM and 285 µM), acquired at 800 MHz, 283 K and with 300 ms mixing time. Only NOEs observed were weak trNOEs of Glc between H1/H3 and H1/H5. c trNOESY spectrum of recombinant HvExoI with Glc and thiocellobiose (57 µM, 285 µM, and 171 µM, respectively), acquired at 800 MHz, 283 K and with 300 ms mixing time. All NOEs were negative. trNOEs defining the ⁴C₁ conformation of non-reducing Glc of bound thiocellobiose are in boxes. Blue lines in (b) and (c) refer to residual noise signals