PDBsum entry 3djh

Isomerase

PDB id: 3djh

Contents

Protein chains

114 a.a. *

Ligands

SO4 ×6

GOL ×4

IPA ×3

Waters ×475

* Residue conservation analysis

PDB id:

3djh

Name:

Isomerase

Title:

Macrophage migration inhibitory factor (mif) at 1.25 a resolution

Structure:

Macrophage migration inhibitory factor. Chain: a, b, c. Synonym: mif, phenylpyruvate tautomerase, glycosylation-inhibiting factor, gif. Engineered: yes

Source:

Homo sapiens. Organism_taxid: 9606. Gene: mif, glif, mmif. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

1.25Å R-factor: 0.170 R-free: 0.186

Authors:

G.V.Crichlow,E.Lolis

Key ref:

G.V.Crichlow et al. (2009). Structural and kinetic analyses of macrophage migration inhibitory factor active site interactions. Biochemistry, 48, 132-139. PubMed id: 19090677

Date:

23-Jun-08 Release date: 23-Dec-08

Protein chains

P14174  (MIF_HUMAN) -  Macrophage migration inhibitory factor from Homo sapiens

Seq: 115 a.a.

Struc: 114 a.a.

Enzyme reactions

• Enzyme class 2: E.C.5.3.2.1 - phenylpyruvate tautomerase.
• Reaction: 3-phenylpyruvate = enol-phenylpyruvate
• Enzyme class 3: E.C.5.3.3.12 - L-dopachrome isomerase.

Pathway:

• Reaction: L-dopachrome = 5,6-dihydroxyindole-2-carboxylate
• Cofactor: Zn(2+)

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

Biochemistry 48:132-139 (2009)

PubMed id: 19090677

Structural and kinetic analyses of macrophage migration inhibitory factor active site interactions.

G.V.Crichlow, J.B.Lubetsky, L.Leng, R.Bucala, E.J.Lolis.

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.