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.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Oxidoreductases / chemistry*
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Amino Acid Sequence
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Animals
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Bacterial Proteins / chemistry
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Carrier Proteins / chemistry*
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Cattle
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Chickens
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Computer Simulation
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Crystallization
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Crystallography, X-Ray
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Flavin-Adenine Dinucleotide / metabolism
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Glycine Decarboxylase Complex
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Glycine Decarboxylase Complex H-Protein
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Glycine Dehydrogenase (Decarboxylating)
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Humans
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Methylamines / chemistry
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Models, Molecular
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Molecular Sequence Data
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Motion
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Mutagenesis, Site-Directed
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Plant Proteins / chemistry*
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Protein Conformation*
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Sequence Alignment
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Sequence Homology, Amino Acid
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Solvents
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Thioctic Acid / chemistry*
Substances
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Bacterial Proteins
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Carrier Proteins
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Glycine Decarboxylase Complex H-Protein
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Methylamines
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Plant Proteins
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Solvents
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Flavin-Adenine Dinucleotide
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Thioctic Acid
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methylamine
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Amino Acid Oxidoreductases
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Glycine Decarboxylase Complex
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Glycine Dehydrogenase (Decarboxylating)