Biomaterial Database

Spatial proximity of two divalent metal ions at the active site of S-adenosylmethionine synthetase. 1981

G D Markham

S-Adenosylmethionine synthetase from Escherichia coli is shown to require 2 divalent metal ions/enzyme subunit for maximal enzymatic activity. In the absence of substrate, the tetrameric enzyme binds 1 Mn(II) ion/subunit, whereas in the presence of a nucleotide substrate, adenylylimidodiphosphate, or the product pyrophosphate, there are two Mn(II)-binding sites/subunit. Electron paramagnetic resonance spectra of Mn(II) bound to the enzyme reveal a spin exchange interaction between 2 Mn(II) ions in complexes of enzyme and Mn(II) which also contain adenosylmethionine, K+, and either pyrophosphate or imidotriphosphate. Since a spin exchange interaction requires orbital overlap between the 2 ions, the metal ions must be bound close to one another, and they may share a common ligand.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008345	Manganese	A trace element with atomic symbol Mn, atomic number 25, and atomic weight 54.94. It is concentrated in cell mitochondria, mostly in the pituitary gland, liver, pancreas, kidney, and bone, influences the synthesis of mucopolysaccharides, stimulates hepatic synthesis of cholesterol and fatty acids, and is a cofactor in many enzymes, including arginase and alkaline phosphatase in the liver. (From AMA Drug Evaluations Annual 1992, p2035)
D008716	Methionine Adenosyltransferase	An enzyme that catalyzes the synthesis of S-adenosylmethionine from methionine and ATP. EC 2.5.1.6.	S-Adenosylmethionine Synthetase,ATP-Methionine S-Adenosyltransferase,ATP Methionine S Adenosyltransferase,Adenosyltransferase, Methionine,S Adenosylmethionine Synthetase,S-Adenosyltransferase, ATP-Methionine,Synthetase, S-Adenosylmethionine
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D004578	Electron Spin Resonance Spectroscopy	A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.	ENDOR,Electron Nuclear Double Resonance,Electron Paramagnetic Resonance,Paramagnetic Resonance,Electron Spin Resonance,Paramagnetic Resonance, Electron,Resonance, Electron Paramagnetic,Resonance, Electron Spin,Resonance, Paramagnetic
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D000266	Adenylyl Imidodiphosphate	5'-Adenylic acid, monoanhydride with imidodiphosphoric acid. An analog of ATP, in which the oxygen atom bridging the beta to the gamma phosphate is replaced by a nitrogen atom. It is a potent competitive inhibitor of soluble and membrane-bound mitochondrial ATPase and also inhibits ATP-dependent reactions of oxidative phosphorylation.	Adenyl Imidodiphosphate,gamma-Imino-ATP,AMP-PNP,AMPPNP,ATP(beta,gamma-NH),Adenosine 5'-(beta,gamma-Imino)triphosphate,Adenylimidodiphosphate,Adenylylimidodiphosphate,Mg AMP-PNP,Mg-5'-Adenylylimidodiphosphate,beta,gamma-imido-ATP,gamma-Imido-ATP,AMP-PNP, Mg,Imidodiphosphate, Adenyl,Imidodiphosphate, Adenylyl,Mg 5' Adenylylimidodiphosphate,Mg AMP PNP,beta,gamma imido ATP,gamma Imido ATP,gamma Imino ATP
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D014166	Transferases	Transferases are enzymes transferring a group, for example, the methyl group or a glycosyl group, from one compound (generally regarded as donor) to another compound (generally regarded as acceptor). The classification is based on the scheme "donor:acceptor group transferase". (Enzyme Nomenclature, 1992) EC 2.	Transferase