ABSTRACT
Mitogen-activated protein kinase-activated protein kinase 2 (MK2 or MAPKAP-K2), a serine/threonine kinase from the p38 mitogen-activated protein kinase signalling pathway, plays an important role in the production of TNF-α and other cytokines. In a previous report, it was shown that MK2 in complex with the selective inhibitor TEI-I01800 adopts an α-helical glycine-rich loop that is induced by the stable nonplanar conformer of TEI-I01800. To understand the mechanism of the structural change, the structure of MK2 bound to TEI-L03090, which lacks the key substituent found in TEI-I01800, was determined. MK2-TEI-L03090 has a ß-sheet glycine-rich loop in common with other kinases, as predicted. This result suggests that a small compound can induce a drastic conformational change in the target protein structure and can be used to design potent and selective inhibitors.
Subject(s)
Heterocyclic Compounds, 3-Ring/chemistry , Intracellular Signaling Peptides and Proteins/chemistry , Models, Molecular , Protein Kinase Inhibitors/chemistry , Protein Serine-Threonine Kinases/chemistry , Pyrazoles/chemistry , Pyrimidines/chemistry , Amino Acid Sequence , Crystallography, X-Ray , Humans , Intracellular Signaling Peptides and Proteins/antagonists & inhibitors , Intracellular Signaling Peptides and Proteins/metabolism , Molecular Sequence Data , Protein Binding , Protein Interaction Domains and Motifs , Protein Serine-Threonine Kinases/antagonists & inhibitors , Protein Serine-Threonine Kinases/metabolism , Protein Structure, Secondary , Recombinant Proteins/chemistry , Recombinant Proteins/metabolism , Structural Homology, ProteinABSTRACT
Mitogen-activated protein kinase-activated protein kinase 2 (MK2 or MAPKAP-K2) is a Ser/Thr kinase from the p38 mitogen-activated protein kinase signalling pathway and plays an important role in inflammatory diseases. The crystal structure of the MK2-TEI-I01800 complex has been reported; its Gly-rich loop was found to form an α-helix, not a ß-sheet as has been observed for other Ser/Thr kinases. TEI-I01800 is 177-fold selective against MK2 compared with CDK2; in order to understand the inhibitory mechanism of TEI-I01800, the cyclin-dependent kinase 2 (CDK2) complex structure with TEI-I01800 was determined at 2.0 Å resolution. Interestingly, the Gly-rich loop of CDK2 formed a ß-sheet that was different from that of MK2. In MK2, TEI-I01800 changed the secondary structure of the Gly-rich loop from a ß-sheet to an α-helix by collision between Leu70 and a p-ethoxyphenyl group at the 7-position and bound to MK2. However, for CDK2, TEI-I01800 bound to CDK2 without this structural change and lost the interaction with the substituent at the 7-position. In summary, the results of this study suggest that the reason for the selectivity of TEI-I01800 is the favourable conformation of TEI-I01800 itself, making it suitable for binding to the α-form MK2.
