The Lipoyl‐Containing Components of the Mammalian Pyruvate Dehydrogenase Complex: Structural Comparison and Subdomain Roles<sup>a</sup>

Roche, Thomas E.; Rahmatullah, Mohammed; Powers‐Greenwood, Susan L.; Radke, Gary A.; Gopalakrishnan, Subramaniam; ␣Chang, Christina L.

doi:10.1111/j.1749-6632.1989.tb14987.x

Cited by 5 publications

(1 citation statement)

References 17 publications

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“…These thermodynamic parameters confirm the conclusions derived from the solubility-based binding assays that lip-LBD2 and lip-LBD3 interact with MBP-BCK to a degree similar to lip-DD. DISCUSSION A prominent feature of the mitochondrial kinases comprising BCK and PDK isoforms is the up-regulation through interaction with their respective E2 cores of ␣-keto acid dehydrogenase complexes (11,17). The lipoyl-containing domains of the E2 cores function both as an anchor and a modulator for activities of the mitochondrial kinases.…”

Section: Interaction Of Lipoic Acid-bearing Domain With Bckd Kinase 3mentioning

confidence: 99%

The C-terminal Hinge Region of Lipoic Acid-bearing Domain of E2b Is Essential for Domain Interaction with Branched-chain α-Keto Acid Dehydrogenase Kinase

Chuang

Wynn

Chuang

2002

Journal of Biological Chemistry

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The branched-chain ␣-keto acid dehydrogenase (BCKD) kinase (abbreviated as BCK) down-regulates activity of the mammalian mitochondrial BCKD complex by reversible phosphorylation of the decarboxylase (E1b) component of the complex. The binding of BCK to the holotransacylase (E2b) core of the BCKD complex results in the stimulation of BCK activity. Here we show that the lipoylated lipoic acid-bearing domain (lip-LBD) (residues 1-84) of E2b alone does not interact with BCK. However, lip-LBD constructs containing various lengths of the C-terminal hinge region of LBD are able to bind to BCK as measured by a newly developed solubility-based binding assay. Isothermal titration calorimetry measurements produced a dissociation constant of 8.06 ؋ 10 ؊6 M and binding enthalpy of -3.68 kcal/mol for the interaction of BCK with a construct containing lip-LBD and the Glu-Glu-Asp-Xaa-Xaa-Glu sequence of the C-terminal hinge region of LBD. These thermodynamic parameters are similar to those obtained for binding of BCK to a lipoylated di-domain construct, which harbors LBD, the entire hinge region, and the downstream subunit-binding domain of E2b. Our data establish that the C-terminal hinge region of LBD containing the above negatively charged residues is essential for the interaction between the lip-LBD construct and BCK.The mammalian mitochondrial branched-chain ␣-keto acid dehydrogenase (BCKD) 1 complex catalyzes the rate-limiting step in the oxidation of branched-chain amino acids leucine, isoleucine, and valine (1). Genetic defects in this macromolecular multienzyme complex result in the accumulation of branched-chain amino acids leading to inheritable maple syrup urine disease. The clinical phenotype includes early onset and often fatal acidosis, neurological derangement, and mental retardation among survivors (1). The mammalian BCKD complex is organized around a cubic core of 24-meric dihydrolipoyl transacylase (E2b), to which multiple copies of branched-chain ␣-keto acid decarboxylase (E1b), dihydrolipoamide dehydrogenase (E3), BCKD kinase (abbreviated as BCK), and BCKD phosphatase are attached through ionic interactions (2-4). The activity of the BCKD complex is tightly regulated by a phosphorylation/dephosphorylation cycle in response to dietary and hormonal signals (5). Phosphorylation of Ser-292 and Ser-302 in the ␣ subunit of E1b by BCK results in the inactivation of the BCKD complex (6).The structures of rat BCK in the apo-, ADP-bound, and ATP␥S-bound forms were recently determined (7). The BCK structures feature a nucleotide-binding (K) domain and a fourhelix bundle (B) domain, which are similar to modules found in bacterial protein-histidine kinases (8) and the related pyruvate dehydrogenase kinase 2 (PDK2) of the mitochondrial pyruvate dehydrogenase complex (PDC) (9). The K domain is highly conserved between BCK and members of the GHL ATPase family (10), with the presence of characteristic N1, G1, F, and G2 boxes and an "ATP lid." In BCK, the direct back-to-back interaction of two opposing K domains produces a d...

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Section: Interaction Of Lipoic Acid-bearing Domain With Bckd Kinase 3mentioning

confidence: 99%

The C-terminal Hinge Region of Lipoic Acid-bearing Domain of E2b Is Essential for Domain Interaction with Branched-chain α-Keto Acid Dehydrogenase Kinase

Chuang

Wynn

Chuang

2002

Journal of Biological Chemistry

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Pyruvate dehydrogenase complex from the primitive insect trypanosomatid, Crithidia fasciculata: dihydrolipoyl dehydrogenase-binding protein has multiple lipoyl domains

Díaz

Komuniecki

1995

Molecular and Biochemical Parasitology

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Sequence similarities within the family of dihydrolipoamide acyltransferases and discovery of a previously unidentified fungal enzyme

Russell

Guest

1991

Biochimica et Biophysica Acta (BBA) - Protein Structure and Mol

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The Lipoyl‐Containing Components of the Mammalian Pyruvate Dehydrogenase Complex: Structural Comparison and Subdomain Roles^a

Cited by 5 publications

References 17 publications

The C-terminal Hinge Region of Lipoic Acid-bearing Domain of E2b Is Essential for Domain Interaction with Branched-chain α-Keto Acid Dehydrogenase Kinase

The C-terminal Hinge Region of Lipoic Acid-bearing Domain of E2b Is Essential for Domain Interaction with Branched-chain α-Keto Acid Dehydrogenase Kinase

Pyruvate dehydrogenase complex from the primitive insect trypanosomatid, Crithidia fasciculata: dihydrolipoyl dehydrogenase-binding protein has multiple lipoyl domains

Sequence similarities within the family of dihydrolipoamide acyltransferases and discovery of a previously unidentified fungal enzyme

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The Lipoyl‐Containing Components of the Mammalian Pyruvate Dehydrogenase Complex: Structural Comparison and Subdomain Rolesa

Cited by 5 publications

References 17 publications

The C-terminal Hinge Region of Lipoic Acid-bearing Domain of E2b Is Essential for Domain Interaction with Branched-chain α-Keto Acid Dehydrogenase Kinase

The C-terminal Hinge Region of Lipoic Acid-bearing Domain of E2b Is Essential for Domain Interaction with Branched-chain α-Keto Acid Dehydrogenase Kinase

Pyruvate dehydrogenase complex from the primitive insect trypanosomatid, Crithidia fasciculata: dihydrolipoyl dehydrogenase-binding protein has multiple lipoyl domains

Sequence similarities within the family of dihydrolipoamide acyltransferases and discovery of a previously unidentified fungal enzyme

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The Lipoyl‐Containing Components of the Mammalian Pyruvate Dehydrogenase Complex: Structural Comparison and Subdomain Roles^a