Figure Legends
Fig. 1 Schematic of the components in the insulin-like growth factor system (top box) and their functional regulation (lower right diagram). IGFBPs tightly bind and sequester IGFs in the serum and inhibit their interaction with the IGF receptor (IGF-1R). IGFBP protease cleavage within the disordered linker domain of the IGFBP releases IGF allowing it to bind to the IGF-R, stimulating intracellular IGF signaling. The crystal structure of the N- and C-domains of IGFBP4 (N-BP-4 (green) and C-BP-4 (blue), respectively) bound to IGF-1 (PDB ID: 2DSR, red) is shown, with the intrinsically disordered linker domain (L-domain) drawn as a dotted line for illustration. In the case of IGFBP2, the N-, C- and the L-domains are each approximately 100 residues in length.
Fig. 2 : (a) Two dimensional [15N-1H] HSQC NMR spectrum of L-h IGFBP2 acquired at 1H resonance frequency of 800 MHz at 20 oC in 50 mM Na-phosphate buffer (pH 6.0) and 100 mM NaCl. The peaks are numbered according to full-length protein (i.e., starting from 97 to 191), the peaks numbered -5 to -1 are a part of the N terminal tag while peak numbers 1 to14 belong to the additional C-terminal residues. (b) The predicted order parameter of L-h IGFBP2 as calculated with TALOS+ using the observed1H, 15N,13Cα,1Hα, C’ chemical shifts.