Abstract:
:The structures of four isomorphous crystals of ternary complexes of chicken heart citrate synthase with D- or L-malate and acetyl coenzyme A or carboxymethyl coenzyme A have been determined by X-ray crystallography and fully refined at 1.9-A resolution. The structures show that both L-malate and D-malate bind in a very similar way in the presence of acetylCoA and that the enzyme conformation is "closed". Hydrogen bond geometry is suggested to account for the difference in binding constants of the two stereoisomers. The structures suggest that steric hindrance can account for the observation that proton exchange of acetyl coenzyme A with solvent is catalyzed by citrate synthase in the presence of L-malate but not D-malate. The ternary complexes with malate reveal the mode of binding of the substrate acetylCoA in the ground state. The carbonyl oxygen of the acetyl group is hydrogen bonded to a water molecule and to histidine 274, allowing unambiguous identification of the orientation of this group. The structures support the hypothesis that carboxymethyl coenzyme A is a transition-state analogue for the enolization step of the reaction (Bayer et al., 1981) and additionally support proposed mechanisms for the condensation reaction (Karpusas et al., 1990; Alter et al., 1990).
journal_name
Biochemistryjournal_title
Biochemistryauthors
Karpusas M,Holland D,Remington SJdoi
10.1021/bi00238a028subject
Has Abstractpub_date
1991-06-18 00:00:00pages
6024-31issue
24eissn
0006-2960issn
1520-4995journal_volume
30pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::The occurrence of isozymes in plant peroxidases is poorly understood. Turnip roots contain seven season-dependent isoperoxidases with distinct physicochemical properties. In the work presented here, multifrequency electron paramagnetic resonance spectroscopy has been used to characterize the Compound I intermediate ob...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi002826j
更新日期:2001-06-12 00:00:00
abstract::The complete amino acid sequence of human liver cytosolic alanine aminotransferase (GPT) (EC 2.6.1.2) is presented. Two primary sets of overlapping fragments were obtained by cleavage of the pyridylethylated protein at methionyl and lysyl bonds with cyanogen bromide and Achromobacter protease I, respectively. Isolated...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00107a013
更新日期:1991-10-29 00:00:00
abstract::While the critical role of the bacterial luciferase alpha subunit in catalysis has been amply documented, the beta subunit was only known to be involved in thermal stability and substrate binding. Two conserved histidyl residues at position 81 and 82 of the beta subunit of Vibrio harveyi luciferase were each mutated t...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00206a023
更新日期:1994-10-11 00:00:00
abstract::Purine nucleoside phosphorylase (PNP) catalyzes the reversible phosphorolysis of purine ribonucleosides and 2'-deoxyribonucleosides, yielding the purine base and (2'-deoxy)ribose 1-phosphate as products. While this enzyme has been extensively studied, several questions with respect to the catalytic mechanism have rema...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.5b01347
更新日期:2016-04-12 00:00:00
abstract::The equilibrium binding of hemoglobin to isolated band 3 protein exhibited positive cooperativity [Hill coefficient = 1.65 +/- 0.1; total number of binding sites at pH 6.6 in 5 mM sodium phosphate buffer = 32 500 +/- 940 pmol/mg; Ka = (3.0 +/- 0.5) X 10(5) M-1]. The binding was reversible and ionic in nature as the bo...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00359a054
更新日期:1986-06-03 00:00:00
abstract::Helix-junction-helix (HJH) motifs are flexible building blocks of RNA architecture that help define the orientation and dynamics of helical domains. They are also frequently involved in adaptive recognition of proteins and small molecules and in the formation of tertiary contacts. Here, we use a battery of nuclear mag...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.6b00285
更新日期:2016-08-16 00:00:00
abstract::Argonaute (AGO) proteins play central roles in nucleic acid-guided interference that regulates gene expression and defend against foreign genetic elements in all life. Although much progress has been made with respect to the function of argonaute proteins in target recognition and cleavage, the detailed mechanism of t...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.8b00213
更新日期:2018-04-17 00:00:00
abstract::The central importance of chorismate enzymes in bacteria, fungi, parasites, and plants combined with their absence in mammals makes them attractive targets for antimicrobials and herbicides. Two of these enzymes, anthranilate synthase (AS) and aminodeoxychorismate synthase (ADCS), are structurally and mechanistically ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.5b00013
更新日期:2015-04-14 00:00:00
abstract::Inflammation and subsequent cyclooxygenase-2 (COX-2) activity has long been linked with the development of cancer, although little is known about any epigenetic effects of COX-2. A product of COX-2 activation, levuglandin (LG) quickly forms covalent bonds with nearby primary amines, such as those in lysine, which lead...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi401673b
更新日期:2014-04-22 00:00:00
abstract::Thioltransferase activity was identified and the enzyme purified to apparent homogeneity from human red blood cells. Activity was measured as glutathione-dependent reduction of the prototype substrate hydroxyethyl disulfide; formation of oxidized glutathione (GSSG) was coupled to NADPH oxidation by GSSG reductase (1 u...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00239a002
更新日期:1991-06-25 00:00:00
abstract::Human genomic clones that span the entire protein S expressed gene (PS alpha) and the 3' two-thirds of the protein S pseudogene (PS beta) have been isolated and characterized. The PS alpha gene is greater than 80 kilobases in length and contains 14 introns and 15 exons, as well as 6 repetitive "Alu" sequences. Exons I...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00486a010
更新日期:1990-08-28 00:00:00
abstract::Ketosteroid isomerase (KSI) from Pseudomonas putida biotype B is a homodimeric enzyme catalyzing an allylic rearrangement of Delta5-3-ketosteroids at rates comparable with the diffusion-controlled limit. The tyrosine triad (Tyr14.Tyr55.Tyr30) forming a hydrogen-bond network in the apolar active site of KSI has been ch...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi015547k
更新日期:2001-11-13 00:00:00
abstract::Phosphodeoxyribomutase from Escherichia coli has been purified to homogeneity. Chromatography on DEAE-Sephadex revealed three peaks of enzyme activity, designated form I, form II, and form III. Form III could be further separated into form III-1 and form III-2 by polyacrylamide gel electrophoresis. The four different ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00674a021
更新日期:1975-02-11 00:00:00
abstract::Vitamin K dependent carboxylation of an exogenous peptide substrate and endogenous protein substrates, vitamin K epoxidation, and reduction of vitamin K epoxide were measured in subcellular fractions from rat liver. The rough microsomal fraction was highly enriched in all four activities; lower levels were found in sm...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00547a019
更新日期:1980-03-18 00:00:00
abstract::Targeting damage to specific sites in the genome represents an attractive approach to manipulating gene function in mammalian cells. To test the applicability of triple-helix formation as a means for achieving precisely timed site-specific damage within a mammalian gene, a triplex-forming oligodeoxyribonucleotide (TFO...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi960881f
更新日期:1996-08-20 00:00:00
abstract::The capsular polysaccharide (CPS) structure of Campylobacter jejuni contributes to its robust fitness. Many strains contain heptose moieties in their CPS units. The precursor heptose is GDP-d-glycero-α-d-manno-heptose; modifications to the stereochemistry at C3-C6 as well as additions of methyl and phosphoramidate gro...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.9b00548
更新日期:2019-09-17 00:00:00
abstract::Transient contacts between denatured polypeptide chains are likely to play an important part in the initial stages of protein aggregation and fibrillation. To analyze the nature of such contacts, we have carried out a protein engineering study of the 102-residue protein U1A, which aggregates transiently in the wild-ty...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi048509k
更新日期:2004-10-19 00:00:00
abstract::Allosteric activators are generally believed to shift the equilibrium distribution of enzyme conformations to favor a catalytically productive structure; the kinetics of conformational exchange is seldom addressed. Several observations suggested that the usual allosteric mechanism might not apply to the activation of ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi200785s
更新日期:2011-10-04 00:00:00
abstract::We have used frequency domain fluorescence techniques to resolve the component emission spectra for several two tryptophan containing proteins (e.g., horse liver alcohol dehydrogenase, sperm whale apomyoglobin, yeast 3-phosphoglycerate kinase, apoazurin from Alcaligenes denitricans). We have first performed multifrequ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00399a047
更新日期:1987-12-15 00:00:00
abstract::A human cDNA, UDPGTh-3, encoding a dihydrotestosterone/5 alpha-androstane-3 alpha,17 beta-diol UDP- glucuronosyltransferase (transferase) has been isolated and characterized. The nucleotide sequence of UDPGTh-3 encodes a 530 amino acid protein with a typical membrane insertion-signal peptide, a membrane-anchoring doma...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00091a015
更新日期:1993-10-12 00:00:00
abstract::Glutaminase (GLS1/2) catalyzes the conversion of L-glutamine to L-glutamate and ammonia. The level of a splice variant of GLS1 (GAC) is elevated in certain cancers, and GAC is specifically inhibited by bis-2-(5-phenylacetimido-1,2,4,thiadiazol-2-yl)ethyl sulfide (BPTES). We report here the first full-length crystal st...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi201613d
更新日期:2011-12-20 00:00:00
abstract::The human, cytosolic enzyme isocitrate dehydrogenase 1 (IDH1) reversibly converts isocitrate to α-ketoglutarate (αKG). Cancer-associated somatic mutations in IDH1 result in a loss of this normal function but a gain in a new or neomorphic ability to convert αKG to the oncometabolite 2-hydroxyglutarate (2HG). To improve...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi400514k
更新日期:2013-07-02 00:00:00
abstract::During catalysis by liver alcohol dehydrogenase (ADH), a water bound to the catalytic zinc is replaced by the oxygen of the substrates. The mechanism might involve a pentacoordinated zinc or a double-displacement reaction with participation by a nearby glutamate residue, as suggested by studies of human ADH3, yeast AD...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.7b00446
更新日期:2017-07-18 00:00:00
abstract::The oxidation of deoxy- and oxyhemerythrin to methemerythrin by Fe(CN)6(3-) has been examined. The first step produces (semi-met)O, a half-oxidized form of hemerythrin which has different spectral and kinetic properties from (semi-met)R which is produced by one-electron reduction of methemerythrin. Further oxidation o...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00559a003
更新日期:1980-09-02 00:00:00
abstract::We have employed a combination of gel retardation, protein-DNA cross-linking, and protein-protein cross-linking techniques to further examine the 2,3,7,8-tetrachlorodibenzo-p- dioxin-(TCDD-) dependent changes in the Ah receptor that result in a DNA-binding conformation. Gel retardation analysis of DNA-Sepharose chroma...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00225a026
更新日期:1991-03-19 00:00:00
abstract::Scaffold/matrix-attached regions (S/MARs) are cis-acting elements with a function outside transcribed regions and in introns. Although they usually augment transcriptional rates, their action is highly context-dependent. We cloned an 800 bp S/MAR element from the upstream border of the human interferon-beta domain at ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi960930o
更新日期:1996-08-27 00:00:00
abstract::Hepatic microsomal cytochrome P-450 from phenobarbital-pretreated rats is destroyed by propyne in a reduced nicotinamide adenine dinucleotide dependent process which also results in vivo in the accumulation of an abnormal green porphyrin. The green porphyrin has been identified by its electronic absorption, mass spect...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00528a033
更新日期:1981-12-08 00:00:00
abstract::FTIR-difference spectroscopy in combination with site-directed mutagenesis has been used to investigate the role of water during the photocycle of bacteriorhodopsin. At least one water molecule is detected which undergoes an increase in H-bonding during the primary bR-->K phototransition. Bands due to water appear in ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00209a005
更新日期:1994-11-01 00:00:00
abstract::The properties of neuronal nitric oxide synthase containing one tetrahydrobiopterin (BH4) per dimer [nNOS(BH4+)] were compared to those of the BH4-free enzyme [nNOS(BH4-)]. The stimulation by BH4 of the formation of L-citrulline at the expense of H2O2 production unambiguously demonstrated that BH4 is essential in coup...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi961931j
更新日期:1996-12-24 00:00:00
abstract::Several snake venoms contain a phospholipase A2 in which position 49 in the active site is occupied by a lysine or a serine instead of the aspartate residue normally found. Although these proteins do not bind Ca2+ and are devoid of catalytic activity, they are still highly specific myotoxins and have recently been sho...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00014a021
更新日期:1995-04-11 00:00:00