title: An asymmetric model for Na+-translocating glutaconyl-CoA decarboxylases.
abstract: Glutaconyl-CoA decarboxylase (Gcd) couples the biotin-dependent decarboxylation of glutaconyl-CoA with the generation of an electrochemical Na(+) gradient. Sequencing of the genes encoding all subunits of the Clostridium symbiosum decarboxylase membrane complex revealed that it comprises two distinct biotin carrier subunits, GcdC(1) and GcdC(2), which differ in the length of a central alanine- and proline-rich linker domain. Co-crystallization of the decarboxylase subunit GcdA with the substrate glutaconyl-CoA, the product crotonyl-CoA, and the substrate analogue glutaryl-CoA, respectively, resulted in a high resolution model for substrate binding and catalysis revealing remarkable structural changes upon substrate binding. Unlike the GcdA structure from Acidaminococcus fermentans, these data suggest that in intact Gcd complexes, GcdA is associated as a tetramer crisscrossed by a network of solvent-filled tunnels.
authors: Biochemie, Fachbereich Chemie, Philipps-Universität Marburg, D-35032 Marburg, Germany.
authors: Daniel
authors: D
authors: Kress
authors: Mikrobiologie, Fachbereich Biologie, Philipps-Universität Marburg, D-35032 Marburg, Germany.
authors: Daniela
authors: D
authors: Brügel
authors: Mikrobiologie, Fachbereich Biologie, Philipps-Universität Marburg, D-35032 Marburg, Germany.
authors: Iris
authors: I
authors: Schall
authors: Biochemie, Fachbereich Medizin, Justus von Liebig-Universität, D-35392 Gieβen, Germany.
authors: Dietmar
authors: D
authors: Linder
authors: Mikrobiologie, Fachbereich Biologie, Philipps-Universität Marburg, D-35032 Marburg, Germany; Max-Plank-Institut für Terrestrische Mikrobiologie, D-35043 Marburg, Germany. Electronic address: buckel@staff.uni-marburg.de.
authors: Wolfgang
authors: W
authors: Buckel
authors: Biochemie, Fachbereich Chemie, Philipps-Universität Marburg, D-35032 Marburg, Germany. Electronic address: essen@chemie.uni-marburg.de.
authors: Lars-Oliver
authors: LO
authors: Essen
mesh_terms: D045850:Acidaminococcus / Q000201:enzymology; D000214:Acyl Coenzyme A / Q000737:chemistry / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002262:Carboxy-Lyases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D048009:Clostridium symbiosum / Q000201:enzymology / Q000235:genetics; D018360:Crystallography, X-Ray; D018698:Glutamic Acid / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D005810:Multigene Family; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D012964:Sodium / Q000378:metabolism*
chemical_list: D000214:Acyl Coenzyme A; D001426:Bacterial Proteins; D021122:Protein Subunits; D018698:Glutamic Acid; C010701:crotonyl-coenzyme A; D012964:Sodium; D002262:Carboxy-Lyases; C023060:glutaconyl CoA decarboxylase