4GUM
Cystal structure of locked-trimer of human MIF
Summary for 4GUM
| Entry DOI | 10.2210/pdb4gum/pdb |
| Descriptor | Macrophage migration inhibitory factor, CHLORIDE ION (3 entities in total) |
| Functional Keywords | alpha/beta mixture, cytokine and isomerase, isomerase |
| Biological source | Homo sapiens (Human) |
| Total number of polymer chains | 9 |
| Total formula weight | 111380.49 |
| Authors | |
| Primary citation | Fan, C.,Rajasekaran, D.,Syed, M.A.,Leng, L.,Loria, J.P.,Bhandari, V.,Bucala, R.,Lolis, E.J. MIF intersubunit disulfide mutant antagonist supports activation of CD74 by endogenous MIF trimer at physiologic concentrations. Proc.Natl.Acad.Sci.USA, 110:10994-10999, 2013 Cited by PubMed Abstract: Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine. In addition to its known receptor-mediated biological activities, MIF possesses a catalytic site of unknown function between subunits of a homotrimer. Each subunit contributes three β-strands to adjacent subunits to form a core seven-stranded β-sheet for each monomer. MIF monomers, dimers, or trimers have been reported, but the active form that binds and activates the MIF receptor (CD74) is still a matter of debate. A cysteine mutant (N110C) that covalently locks MIF into a trimer by forming a disulfide with Cys-80 of an adjacent subunit is used to study this issue. Partial catalytic activity and receptor binding to CD74 are retained by N110C (locked trimer), but there is no cellular signaling. Wild-type MIF-induced cellular signaling, in vivo lung neutrophil accumulation, and alveolar permeability are inhibited with a fivefold excess of N110C. NMR and size-exclusion chromatography with light scattering reveal that N110C can form a higher-order oligomer in equilibrium with a single locked trimer. The X-ray structure confirms a local conformational change that disrupts the subunit interface and results in global changes responsible for the oligomeric form. The structure also confirms these changes are consistent for the partial catalytic and receptor binding activities. The absence of any potential monomer and the retention of partial catalytic and receptor binding activities despite changes in conformation (and dynamics) in the mutant support an endogenous MIF trimer that binds and activates CD74 at nanomolar concentrations. This conclusion has implications for therapeutic development. PubMed: 23776208DOI: 10.1073/pnas.1221817110 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.33 Å) |
Structure validation
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