Structure activity studies of the cytokine macrophage migration inhibitory factor (MIF) reveal a critical role for its carboxy terminus.
Carboxy-truncated mutants of human MIF (MIF(1-104) and MIF(1-109)) were used in structure activity studies. CD spectroscopy revealed an overall structural similarity between the mutants and MIF. Denaturant-induced unfolding demonstrated that the C-terminus contributed significantly to the conformational stability of MIF. This appears to be due to the formation of two C-terminal beta-strands. The mutants were enzymatically active, exhibiting half of the enzymatic redox activity of MIF. However, immunological analysis showed that deletion of both 5 and 10 C-terminal residues resulted in loss of the macrophage activating properties of MIF, providing functional evidence that the C-terminus is important for immunological activity and trimer formation. A more detailed study of the C-terminus may assist in identifying the molecular basis for the immunological and enzymatic activities of MIF.
Mischke
R
R
Laboratory of Biochemistry, Chair for Interfacial Engineering, University of Stuttgart, Germany.
Gessner
A
A
Kapurniotu
A
A
Jüttner
S
S
Kleemann
R
R
Brunner
H
H
Bernhagen
J
J
D000595:Amino Acid Sequence; D000818:Animals; D000981:Antiprotozoal Agents; D001681:Biological Assay; D002942:Circular Dichroism; D017931:DNA Primers; D019791:Guanidine; D006146:Guanidines; D006801:Humans; D019169:Jurkat Cells; D018320:Leishmania major / Q000187:drug effects; D046911:Macromolecular Substances; D008263:Macrophage Migration-Inhibitory Factors / Q000096:biosynthesis / Q000737:chemistry* / Q000494:pharmacology*; D008961:Models, Structural; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009250:NADP Transhydrogenases / Q000378:metabolism; D010446:Peptide Fragments / Q000096:biosynthesis / Q000737:chemistry / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship; D013816:Thermodynamics
D000981:Antiprotozoal Agents; D017931:DNA Primers; D006146:Guanidines; D046911:Macromolecular Substances; D008263:Macrophage Migration-Inhibitory Factors; D010446:Peptide Fragments; D011994:Recombinant Proteins; D009250:NADP Transhydrogenases; D019791:Guanidine