title: The lipoamide arm in the glycine decarboxylase complex is not freely swinging.
abstract: Glycine decarboxylase consists of four protein components. Its structural and mechanistic heart is provided by the lipoic acid-containing H-protein which undergoes a cycle of reductive methylamination, methylamine transfer and electron transfer. Lipoic acid attached to a specific lysine side chain is assumed to act as a 'swinging arm' conveying the reactive dithiolane ring from one catalytic centre to another. The X-ray crystal structures of two forms of the H-protein have been determined. The lipoate cofactor is located in the loop of a hairpin configuration but following methylamine transfer it is pivoted to bind into a cleft at the surface of the H-protein. The lipoamide-methylamine arm is, therefore, not free to move in aqueous solvent.
authors.affiliation: Institut de Biologie Structurale, Centre National de la Recherche Scientifique et Commisariat à l'Energie Atomique, Grenoble, France.
authors.forename: C
authors.initials: C
authors.lastname: Cohen-Addad
authors.forename: S
authors.initials: S
authors.lastname: Pares
authors.forename: L
authors.initials: L
authors.lastname: Sieker
authors.forename: M
authors.initials: M
authors.lastname: Neuburger
authors.forename: R
authors.initials: R
authors.lastname: Douce
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000737:chemistry*; D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry; D002352:Carrier Proteins / Q000737:chemistry*; D002417:Cattle; D002645:Chickens; D003198:Computer Simulation; D003460:Crystallization; D018360:Crystallography, X-Ray; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism; D050959:Glycine Decarboxylase Complex; D050961:Glycine Decarboxylase Complex H-Protein; D050841:Glycine Dehydrogenase (Decarboxylating); D006801:Humans; D008744:Methylamines / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009038:Motion; D016297:Mutagenesis, Site-Directed; D010940:Plant Proteins / Q000737:chemistry*; D011487:Protein Conformation; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012997:Solvents; D008063:Thioctic Acid / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D050961:Glycine Decarboxylase Complex H-Protein; D008744:Methylamines; D010940:Plant Proteins; D012997:Solvents; D005182:Flavin-Adenine Dinucleotide; D008063:Thioctic Acid; C027451:methylamine; D000594:Amino Acid Oxidoreductases; D050959:Glycine Decarboxylase Complex; D050841:Glycine Dehydrogenase (Decarboxylating)