3crl

From Proteopedia

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Template:STRUCTURE 3crl

Crystal structure of the PDHK2-L2 complex.

Overview

PDHK2 is a mitochondrial protein kinase that phosphorylates pyruvate dehydrogenase complex thereby down-regulating the oxidation of pyruvate. Here, we present the crystal structure of PDHK2 bound to the inner lipoyl bearing domain of dihydrolipoamide transacetylase (L2) determined with or without bound adenylyl imidodiphosphate (App(NH)p). Both structures reveal a PDHK2 dimer complexed with two L2 domains. Comparison with apo-PDHK2 shows that L2 binding causes re-arrangements in PDHK2 structure that affect the L2- and E1-binding sites. Significant differences are found between PDHK2 and PDHK3 with respect to the structure of their lipoyllysine-binding cavities, providing the first structural support to a number of studies showing that these isozymes are markedly different with respect to their affinity for L2 domain. Both structures display a novel type II potassium-binding site located on the PDHK2 interface with L2 domain. Binding of potassium ion at this site rigidifies the interface and appears to be critical in determining the strength of L2 binding. Evidence is also presented that potassium ions are indispensable for the cross-talk between the nucleotide- and L2-binding sites of PDHK2. The latter is believed to be essential for the movement of PDHK2 along the surface of the transacetylase scaffold.

About this Structure

3CRL is a Protein complex structure of sequences from Homo sapiens and Rattus norvegicus. Full crystallographic information is available from OCA.

Reference

Structural and functional insights into the molecular mechanisms responsible for the regulation of pyruvate dehydrogenase kinase 2., Green T, Grigorian A, Klyuyeva A, Tuganova A, Luo M, Popov KM, J Biol Chem. 2008 Apr 3;. PMID:18387944 Page seeded by OCA on Wed Apr 30 13:44:07 2008