Insight into small molecule binding to the neonatal Fc receptor by X-ray crystallography and 100 kHz magic-angle-spinning NMR
Fig 5
CSPs (Δδ) indicate structural changes in FcRnECD upon ligand binding.
(A) CSPs of all assigned amino acids in FcRnECD upon binding to UCB-FcRn-303, calculated with Δδ = MIN{SQRT[(Δδ(1H))2 + (Δδ(13C)/10)2 + (Δδ(15N)/5)2]} (standard deviation = 0.015 ppm). The changes were measured in 3D (H)CANH MAS NMR spectra. (B) CSPs upon UCB-FcRn-303 binding to FcRnECD in 2D planes of 3D (H)CANH spectra with (black) and without (blue) the ligand, both recorded in the presence of 3% DMSO. (C) Structural view of UCB-FcRn-303 (red) bound to FcRnECD with assigned residues in stick representation color-coded according to their CSP (Δδ < 0.02, white; 0.02 < Δδ < 0.03, cyan; 0.03 < Δδ < 0.04, marine; 0.04 < Δδ, dark blue). (D) Structural view of FcRnECD in complex with UCB-FcRn-303 (red) with the same color-coding of changes in chemical-shifts as in (C). All chemical-shifts can be found in S1 Table, S2 Data, and in the BMRB (accession number 27437). BMRB, Biological Magnetic Resonance Data Bank; CSP, chemical-shift perturbation; FcRn, neonatal Fc receptor; FcRnECD, extracellular domain of the neonatal Fc receptor.