2q8y
From Proteopedia
Structural insight into the enzymatic mechanism of the phophothreonine lyase
Structural highlights
Function[VRP3_SALEN] Not known. This protein is involved in the virulence of salmonellas. [MK07_HUMAN] Plays a role in various cellular processes such as proliferation, differentiation and cell survival. The upstream activator of MAPK7 is the MAPK kinase MAP2K5. Upon activation, it translocates to the nucleus and phosphorylates various downstream targets including MEF2C. EGF activates MAPK7 through a Ras-independent and MAP2K5-dependent pathway. May have a role in muscle cell differentiation. May be important for endothelial function and maintenance of blood vessel integrity. MAP2K5 and MAPK7 interact specifically with one another and not with MEK1/ERK1 or MEK2/ERK2 pathways. Phosphorylates SGK1 at Ser-78 and this is required for growth factor-induced cell cycle progression. Involved in the regulation of p53/TP53 by disrupting the PML-MDM2 interaction.[1] [2] [3] [4] [5] Publication Abstract from PubMedThe OspF family of phosphothreonine lyase, including SpvC from Salmonella, irreversibly inactivates the dual-phosphorylated host MAPKs (pT-X-pY) through beta elimination. We determined crystal structures of SpvC and its complex with a phosphopeptide substrate. SpvC adopts a unique fold of alpha/beta type. The disordered N terminus harbors a canonical D motif for MAPK substrate docking. The enzyme-substrate complex structure indicates that recognition of the phosphotyrosine followed by insertion of the threonine phosphate into an arginine pocket places the phosphothreonine into the enzyme active site. This requires the conformational flexibility of pT-X-pY, which suggests that p38 (pT-G-pY) is likely the preferred physiological substrate. Structure-based biochemical and enzymatic analysis allows us to propose a general acid/base mechanism for beta elimination reaction catalyzed by the phosphothreonine lyase. The mechanism described here provides a structural understanding of MAPK inactivation by a family of pathogenic effectors conserved in plant and animal systems and may also open a new route for biological catalysis. Structural insights into the enzymatic mechanism of the pathogenic MAPK phosphothreonine lyase.,Zhu Y, Li H, Long C, Hu L, Xu H, Liu L, Chen S, Wang DC, Shao F Mol Cell. 2007 Dec 14;28(5):899-913. Epub 2007 Nov 29. PMID:18060821[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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