3CE4

Structure of Macrophage Migration Inhibitory Factor Covalently Inhibited by PMSF Treatment

Summary for 3CE4

• Entry DOI: 10.2210/pdb3ce4/pdb
• Descriptor: Macrophage migration inhibitory factor, SULFATE ION, phenylmethanesulfonic acid, ... (6 entities in total)
• Functional Keywords: covalent modification, covalent inhibition, cytokine, inflammatory response, isomerase, phosphoprotein
• Biological source: Homo sapiens (Human)
• Cellular location: Secreted : P14174
• Total number of polymer chains: 3
• Total formula weight: 38458.56

Authors

Crichlow, G.V.,Lolis, E. (deposition date: 2008-02-28, release date: 2008-12-30, Last modification date: 2024-10-30)

Primary citation

Crichlow, G.V.,Lubetsky, J.B.,Leng, L.,Bucala, R.,Lolis, E.J.
Structural and kinetic analyses of macrophage migration inhibitory factor active site interactions.
Biochemistry, 48:132-139, 2009

PubMed Abstract: Macrophage migration inhibitory factor (MIF) is a secreted protein expressed in numerous cell types that counters the antiinflammatory effects of glucocorticoids and has been implicated in sepsis, cancer, and certain autoimmune diseases. Interestingly, the structure of MIF contains a catalytic site resembling the tautomerase/isomerase sites of microbial enzymes. While bona fide physiological substrates remain unknown, model substrates have been identified. Selected compounds that bind in the tautomerase active site also inhibit biological functions of MIF. It had previously been shown that the acetaminophen metabolite, N-acetyl-p-benzoquinone imine (NAPQI), covalently binds to the active site of MIF. In this study, kinetic data indicate that NAPQI inhibits MIF both covalently and noncovalently. The structure of MIF cocrystallized with NAPQI reveals that the NAPQI has undergone a chemical alteration forming an acetaminophen dimer (bi-APAP) and binds noncovalently to MIF at the mouth of the active site. We also find that the commonly used protease inhibitor, phenylmethylsulfonyl fluoride (PMSF), forms a covalent complex with MIF and inhibits the tautomerase activity. Crystallographic analysis reveals the formation of a stable, novel covalent bond for PMSF between the catalytic nitrogen of the N-terminal proline and the sulfur of PMSF with complete, well-defined electron density in all three active sites of the MIF homotrimer. Conclusions are drawn from the structures of these two MIF-inhibitor complexes regarding the design of novel compounds that may provide more potent reversible and irreversible inhibition of MIF.

PubMed: 19090677
DOI: 10.1021/bi8014423

Experimental method

X-RAY DIFFRACTION (1.55 Å)