Publications

• Crystal structure of the Schiff base intermediate prior to decarboxylation in the catalytic cycle of aspartate alpha-decarboxylase.

  Lee B.I., Suh S.W.

  l-Aspartate alpha-decarboxylase (ADC), encoded by the panD gene, catalyzes the conversion of l-aspartate into beta-alanine. In the microorganisms, beta-alanine is required for the synthesis of pantothenate (vitamin B(5)), which is the precursor of 4'-phosphopantetheine and coenzyme A. We have dete ... >> More

  l-Aspartate alpha-decarboxylase (ADC), encoded by the panD gene, catalyzes the conversion of l-aspartate into beta-alanine. In the microorganisms, beta-alanine is required for the synthesis of pantothenate (vitamin B(5)), which is the precursor of 4'-phosphopantetheine and coenzyme A. We have determined the crystal structure of Helicobacter pylori ADC, a tetrameric enzyme, in two forms: the apo structure at 2.0 A resolution and the isoasparagine complex structure at 1.55 A resolution. All subunits of the tetramer are self-processed at the Gly24-Ser25 linkage, producing the smaller beta chain (residues 1-24) and the larger alpha chain (residues 25-117). Each subunit contains nine beta-strands and three alpha-helices; it is folded into the double-psi beta-barrel structure. In the apo structure, the new amino terminus of the alpha chain, Ser25, is converted into a pyruvoyl group. In the isoasparagine complex structure, the substrate analog is covalently attached to the pyruvoyl group. This structure represents the enzyme-substrate Schiff base intermediate that was proposed to form prior to the decarboxylation step in the catalytic cycle of ADC. Thus our study provides direct structural evidence for the reaction mechanism of ADC. << Less

  J. Mol. Biol. 340:1-7(2004) [PubMed] [EuropePMC]

• Crystal structure of aspartate decarboxylase at 2.2-A resolution provides evidence for an ester in protein self-processing.

  Albert A., Dhanaraj V., Genschel U., Khan G., Ramjee M.K., Pulido R., Sibanda B.L., von Delft F., Witty M., Blundell T.L., Smith A.G., Abell C.

  The structure of L-aspartate-alpha-decarboxylase from E. coli has been determined at 2.2 A resolution. The enzyme is a tetramer with pseudofour-fold rotational symmetry. The subunits are six-stranded beta-barrels capped by small alpha-helices at each end. The active sites are located between adjac ... >> More

  The structure of L-aspartate-alpha-decarboxylase from E. coli has been determined at 2.2 A resolution. The enzyme is a tetramer with pseudofour-fold rotational symmetry. The subunits are six-stranded beta-barrels capped by small alpha-helices at each end. The active sites are located between adjacent subunits. The electron density provides evidence for catalytic pyruvoyl groups at three active sites and an ester at the fourth. The ester is an intermediate in the autocatalytic self-processing leading to formation of the pyruvoyl group. This unprecedented structure provides novel insights into the general phenomenon of protein processing. << Less

  Nat. Struct. Biol. 5:289-293(1998) [PubMed] [EuropePMC]

• Crystal structure of uncleaved L-aspartate-alpha-decarboxylase from Mycobacterium tuberculosis.

  Gopalan G., Chopra S., Ranganathan A., Swaminathan K.

  L-aspartate-alpha-decarboxylase (ADC) is a critical regulatory enzyme in the pantothenate biosynthetic pathway and belongs to a small class of self-cleaving and pyruvoyl-dependent amino acid decarboxylases. The expression level of ADC in Mycobacterium tuberculosis (Mtb) was confirmed by cDNA analy ... >> More

  L-aspartate-alpha-decarboxylase (ADC) is a critical regulatory enzyme in the pantothenate biosynthetic pathway and belongs to a small class of self-cleaving and pyruvoyl-dependent amino acid decarboxylases. The expression level of ADC in Mycobacterium tuberculosis (Mtb) was confirmed by cDNA analysis, immunoblotting with an anti-ADC polyclonal antibody using whole cell lysate and immunoelectron microscopy. The recombinant ADC proenzyme from Mycobacterium tuberculosis (MtbADC) was overexpressed in E. coli and the protein structure was determined at 2.99 A resolution. The proteins fold into the double-psi beta-barrel structure. The subunits of the two tetramers (there are eight ADC molecules in the asymmetric unit) form pseudo fourfold rotational symmetry, similar to the E. coli ADC proenzyme structure. As pantothenate is synthesized in microorganisms, plants, and fungi but not in animals, structure elucidation of Mtb ADC is of substantial interest for structure-based drug development. << Less

  Proteins 65:796-802(2006) [PubMed] [EuropePMC]