Asp295 Stabilizes the Active-Site Loop Structure of Pyruvate Dehydrogenase, Facilitating Phosphorylation of Ser292 by Pyruvate Dehydrogenase-Kinase
Figure 1
Molecular modeling and in silico mutagenesis of the active-site loop of AtPDC E1α. (a) Alignment of residues in the active-site loop of α-ketoacid dehydrogenase E1α sequences. Numbering is based upon the A. thaliana PDC E1α sequence. The plant mtPDC sequence is identical in Pisum sativum, A. thaliana, Glycine max, Lycopersicon esculentum, Solanum tuberosum, Beta vulgaris, Nicotiana tabacum, Populus hybrida, Lotus corniculatus, Medicago truncatula, Zea mays, and Oryza sativum. The mammalian PDC sequence is identical in Rattus norvegicus, Mus musculus, and Homo sapiens. The nematode PDC sequence is identical in Ascaris suum and Caenorhabditis elegans. The yeast PDC sequence is identical in Saccharomyces cerevisiae, Schizosaccharomyces pombe, and Kluyveromyces lactis. Bacterial PDC sequences are identical from Bacillus subtilis and Bacillus stearothermophilus. The mammalian BCKDC sequence is identical in H. sapiens, M. musculus, and Ovis aries. The bacterial BCKDC sequence is from B. subtilis. The carats denote the Asp and Gly residues targeted in this study. The red underlined Ser residues correspond to mammalian pyruvate dehydrogenase phosphorylation sites 1 and 2 and mammalian BCKDC phosphorylation site 2. (b) The consensus active-site loop primary sequence presented as output from the WebLogo program [9]. (c) Carbon-alpha trace from modeling of residues His-291 to Arg-301 in the active site loop of AtE1α. The same colors have been used for each residue in all panels. Hydrogen bonds are indicated with green dashed lines. Traces were built using Swiss-PDB viewer (version 3.7).
