Fig. 3 : Characterization of the interaction of the IGFs with
L-h IGFBP2. Sensorgrams of (a) IG F-1, (b) IGF-2 immobilized on
the surface of a CM5 chip with L-h IGFBP2 as analyte. (c) Overlay
of the 2D [15N-1H] HSQC spectra
of L-h IGFBP2 (blue) and IGF-1: L-h IGFBP2 (red). Inset
shows an expanded view of the region where residues show maximum
chemical shift perturbations (residues 150-170). (d) Combined
(15N and 1HN) chemical shift
difference plot for L-h IGFBP2 residues upon addition of IGF-1,
calculated using
.
The dotted line is shown at one standard deviation of the chemical shift
differences. (e) Reported proteolysis sites on L-h IGFBP2. (f)
Residues of the linker domain were analyzed for their predicted
propensity to lie within MoRF motifs using the web-based program
MoRFpred. A line between the peak centers of the red and blue signals
for L152 and R156 residues shows the largest chemical shift deviations
(in the insert, Fig. 3c ).
Fig. 4 : R2, R1ρ, and
het-NOE plots for L-h IGFBP2 (blue) and IGF-1: L-h IGFBP2
(red) measured at 1H resonance frequency of 800 MHz.
A-asterisks mark signals with overlap.
Fig. 5: Spectral density function values at J (0),J (ω N), andJ (0.87ω H) frequencies for L-h IGFBP2
(left) and the L-hIGFBP2:IGF-1 (right) complex at a 1H
resonance frequency of 800 MHz. A-asterisks mark signals with overlap.
Fig. 6: The difference in S2 values
(calculated using Eq. 1) between the free and bound forms of
L-h IGFBP2 as estimated from J (0) andJ (ωN) calculated from R1ρ.
Fig. 7: Predicted structure of full-length IGFBP2 from
AlphaFold protein structure database where the disordered linker domain
is represented in red, starting from A97 residue to C191 as marked, with
N- and C-terminal domains of FL-IGFBP2 represented in cyan and blue
respectively. The helix in the linker domain was predicted by Alpha Fold
only (https://alphafold.ebi.ac.uk/) and consistent with the fact
that K150-E161 is more ordered in IGFBP2 as we can see from Fig.
S4