2BAJ

p38alpha bound to pyrazolourea

Summary for 2BAJ

• Entry DOI: 10.2210/pdb2baj/pdb
• Related: 2BAK 2BAL 2BAQ
• Descriptor: Mitogen-activated protein kinase 14, 1-(3-tert-butyl-1-phenyl-1H-pyrazol-5-yl)-3-(2,3-dichlorophenyl)urea (3 entities in total)
• Functional Keywords: mitogen activated protein kinase, transferase
• Biological source: Homo sapiens (human)
• Cellular location: Cytoplasm: Q16539
• Total number of polymer chains: 1
• Total formula weight: 42444.18

Authors

Gerhardt, S.,Pauptit, R.A.,Read, J.,Breed, J.,Norman, R.A.,Ward, W.H. (deposition date: 2005-10-14, release date: 2005-12-06, Last modification date: 2024-02-14)

Primary citation

Sullivan, J.E.,Holdgate, G.A.,Campbell, D.,Timms, D.,Gerhardt, S.,Breed, J.,Breeze, A.L.,Bermingham, A.,Pauptit, R.A.,Norman, R.A.,Embrey, K.J.,Read, J.,Vanscyoc, W.S.,Ward, W.H.
Prevention of MKK6-Dependent Activation by Binding to p38alpha MAP Kinase
Biochemistry, 44:16475-16490, 2005

PubMed Abstract: Inhibition of p38alpha MAP kinase is a potential approach for the treatment of inflammatory disorders. MKK6-dependent phosphorylation on the activation loop of p38alpha increases its catalytic activity and affinity for ATP. An inhibitor, BIRB796, binds at a site used by the purine moiety of ATP and extends into a "selectivity pocket", which is not used by ATP. It displaces the Asp168-Phe169-Gly170 motif at the start of the activation loop, promoting a "DFG-out" conformation. Some other inhibitors bind only in the purine site, with p38alpha remaining in a "DFG-in" conformation. We now demonstrate that selectivity pocket compounds prevent MKK6-dependent activation of p38alpha in addition to inhibiting catalysis by activated p38alpha. Inhibitors using only the purine site do not prevent MKK6-dependent activation. We present kinetic analyses of seven inhibitors, whose crystal structures as complexes with p38alpha have been determined. This work includes four new crystal structures and a novel assay to measure K(d) for nonactivated p38alpha. Selectivity pocket compounds associate with p38alpha over 30-fold more slowly than purine site compounds, apparently due to low abundance of the DFG-out conformation. At concentrations that inhibit cellular production of an inflammatory cytokine, TNFalpha, selectivity pocket compounds decrease levels of phosphorylated p38alpha and beta. Stabilization of a DFG-out conformation appears to interfere with recognition of p38alpha as a substrate by MKK6. ATP competes less effectively for prevention of activation than for inhibition of catalysis. By binding to a different conformation of the enzyme, compounds that prevent activation offer an alternative approach to modulation of p38alpha.

PubMed: 16342939
DOI: 10.1021/bi051714v

Experimental method

X-RAY DIFFRACTION (2.25 Å)