Fig 2: Effect of compounds on TNF:TNFR1 stoichiometry.a Analytical size exclusion chromatography (AnSEC) of human (h) TNF alone (blue trace), hTNF + UCB-5307 (red trace), hTNF + 3.2-fold excess hTNFR1 (green trace) and hTNF + 3.2-fold excess hTNFR1 + 690 µM UCB-5307 (brown trace). Expected migration position of hTNF with two and three receptors bound are indicated by arrows. Standard trace shown in Supplementary Fig. 5. b AnSEC comparing effect of 690 µM UCB-5307 on preformed hTNF/hTNFR1 complex (3.2-fold excess hTNFR1) (red trace) vs. hTNF preloaded with UCB-5307 followed by addition of 3.2-fold excess hTNFR1 (blue trace) as in experiment (a). Source data are provided as a Source Data file.

Fig 3: Fragments bind to TNF with slow-binding kinetics.a SPR depicts the binding of UCB-6786 to immobilised TNF. b The analogue, UCB-6876, specifically binds to immobilised TNF (solid black circles) but not to control proteins, capture antibody plus TNFR1 (solid black squares), capture antibody (solid black triangle pointed down) or TNFR1 (solid black triangle pointed up). c Kinetic analysis of UCB-6876 using the Biacore T100 showing slow association and dissociation rates.

Fig 4: Crystal structure of human TNF with UCB-6876.a Top and side views of TNF (green ribbons) with UCB-6876 bound (orange sticks). b Detail showing the electron density of UCB-6876 and MPD bound within the TNF homotrimer. Monomers B (light green) and C (green) are shown surface rendered. Contour level of the electron density is set at 1 sigma. MPD occupies a space next to UCB-6876. Subsequent molecules described in this paper were modified to have chemical groups occupying the space where MPD was bound. c Detail of the compound-binding pocket within the TNF homotrimer, with key residues involved in binding highlighted (sticks and labels). d Side view of apo-TNF (left image) and UCB-6876 bound TNF (right image) revealing the distorted AC receptor-binding site (selected residues involved in TNFR1 binding are highlighted red).