Abstract:
:Hexose-1-phosphate uridylyltransferase catalyzes the interconversion of UDP-galactose and glucose-1-P with UDP-glucose and galactose-1-P by a double-displacement mechanism through a covalent intermediate (E-UMP), in which UMP is bonded to one of two histidine residues at the active site, H164 or H166. To identify which histidine is the nucleophilic catalyst, we prepared two specific mutants of the enzyme from Escherichia coli, H164G and H166G, in each of which the imidazole ring and methylene carbon of one histidine are deleted. To determine whether the function of the deleted imidazole in these mutants could be carried out by the imidazole ring in uridine 5'-(phosphoimidazolate) (UMP-Im), we examined the mutant proteins for catalytic activity in the reaction of UMP-Im with glucose-1-P to form UDP-glucose and imidazole. The mutant H166G catalyzes this reaction, as well as the reverse reaction, by a sequential kinetic mechanism involving ternary complexes as intermediates. The mutant enzyme also accepts galactose-1-P as a substrate to form UDP-galactose. Hexose-1-P uridylyltransferase does not catalyze these reactions, and H166G does not catalyze the wild-type reaction. The substrate Km values for the mutant enzyme are similar to those for hexose-1-P uridylyltransferase. The value of kcat in the direction of UDP-glucose formation is 1.31 +/- 0.01 s-1, compared with 350 s-1 for hexose-1-P uridylyltransferase, and in the reverse direction kcat is 4.8 +/- 0.4 s-1, compared with 960 s-1 for the wild-type enzyme.(ABSTRACT TRUNCATED AT 250 WORDS)
journal_name
Biochemistryjournal_title
Biochemistryauthors
Kim J,Ruzicka F,Frey PAdoi
10.1021/bi00499a003subject
Has Abstractpub_date
1990-11-27 00:00:00pages
10590-3issue
47eissn
0006-2960issn
1520-4995journal_volume
29pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::Sensory rhodopsin I (SRI) is a seven-transmembrane helix retinylidene protein that mediates color-sensitive phototaxis responses through its bound transducer HtrI in the archaeon Halobacterium salinarum. Deprotonation of the Schiff base attachment site of the chromophore accompanies formation of the SRI signaling stat...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi991180w
更新日期:1999-10-05 00:00:00
abstract::Miniproteins reduce the complexity of the protein-folding problem allowing systematic studies of contributions to protein folding and stabilization. Here, we describe the rational redesign of a miniprotein, PPα, comprising a polyproline II helix, a loop, and an α helix. The redesign provides a de novo framework for in...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.9b00067
更新日期:2019-07-16 00:00:00
abstract::31P NMR spectra were obtained from poly(dA-dT) . poly(dA-dT) fibers which gave an X-ray diffraction pattern similar to that of the A form of natural deoxyribonucleic acid (DNA). The analysis of the line shape indicated that the A form of poly(dA-dT) . poly(dA-dT) has a single uniform backbone conformation; the orienta...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00507a013
更新日期:1981-02-17 00:00:00
abstract::The structure of the subgel phase of dipalmitoylphosphatidylglycerol (DPPG) has been analyzed by X-ray diffraction techniques. Diffraction recorded from highly oriented DPPG specimens in the subgel phase extends to 2-A resolution. There are sharp lamellar reflections on the meridian, and other reflections lie on a ser...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00350a003
更新日期:1986-01-28 00:00:00
abstract::X-ray crystallographic data have implicated Arg-292 as the residue responsible for the preferred side-chain substrate specificity of aspartate aminotransferase. It forms a salt bridge with the beta or gamma carboxylate group of the substrate [Kirsch, J. F., Eichele, G., Ford, G. C., Vincent, M. G., Jansonius, J. N., G...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00412a052
更新日期:1988-06-14 00:00:00
abstract::Mdm2 negatively regulates p53 by inhibiting its transcriptional activity and promoting its degradation by functioning as an E3 ubiquitin ligase. The primary p53 binding site on mdm2 is located in its N-terminal domain. Through binding to p53 at its N-terminal transactivation domain, mdm2 directly blocks the transcript...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi060661u
更新日期:2006-08-01 00:00:00
abstract::Sin3 forms the scaffold for a multiprotein corepressor complex that silences transcription via the action of histone deacetylases. Sin3 is recruited to the DNA by several DNA binding repressors, such as the helix-loop-helix proteins of the Mad family. Here, we elaborate on the Mad-Sin3 interaction based on a binding s...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0355645
更新日期:2004-01-13 00:00:00
abstract::Protein kinase C-related kinases (PRKs) are serine/threonine kinases that are members of the protein kinase C superfamily and can be activated by binding to members of the Rho family of small G proteins via a Rho binding motif known as an HR1 domain. The PRKs contain three tandem HR1 domains at their N-termini. The st...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi200039u
更新日期:2011-04-12 00:00:00
abstract::The DNA binding of three platinum(II) intercalation reagents has been studied and found to depend upon base composition, the nature of the intercalator, and the ionic strength of the solvent medium. In 0.2 M NaCl, binding data for calf thymus DNA show the association constants to be approximately 10(4) M-1. The bindin...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00593a003
更新日期:1979-12-25 00:00:00
abstract::In contrast to FK506 binding proteins and cyclophilins, the parvulin family of peptidyl-prolyl cis/trans isomerases (PPIases; E.C. 5.2.1.8) cannot be inhibited by either FK506 or cyclosporin A. We have found that juglone, 5-hydroxy-1,4-naphthoquinone, irreversibly inhibits the enzymatic activity of several parvulins, ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi973162p
更新日期:1998-04-28 00:00:00
abstract::The crystal structure of the particulate methane monooxygenase (pMMO) from Methylococcus capsulatus (Bath) has been reported recently [Lieberman, R. L., and Rosenzweig, A. C. (2005) Crystal structure of a membrane-bound metalloenzyme that catalyses the biological oxidation of methane, Nature 434, 177-182]. Subsequent ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi700883g
更新日期:2007-12-04 00:00:00
abstract::We find that specific oxidation for the Met-192 residue in delta-chymotrypsin to methionine sulfoxide results in a twofold increase in Km(app) and unchanged kcat in the hydrolysis of N-acetyl mono(amino acid) amide substrates. However, the catalyzed hydrolyses of N-acetyl dipeptide amide substrates by (methionine sulf...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00664a006
更新日期:1976-09-21 00:00:00
abstract::Holliday junctions are central intermediates in the process of genetic recombination. These DNA molecules contain four double helices that flank a central branch point, so that each of the four strands that constitute the junction is associated with two different helices. Previously, we have shown that such branched j...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00003a026
更新日期:1995-01-24 00:00:00
abstract::The photocycle of 124 kDa phytochrome A from Avena sativa was studied by Fourier-transform infrared spectroscopy at low temperatures. Difference spectra between the parent state Pr and the intermediates of the Pr-->Pfr pathway, i.e. lumi-R, meta-Ra, and meta-Rc, and between Pfr and the intermediates of the Pfr-->Pr pa...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi960960r
更新日期:1996-08-20 00:00:00
abstract::Dipeptide substrates for metalloendoproteases have previously been shown to block biological processes requiring membrane fusion. Thus, we employed such compounds as potential inhibitors of the insulin-dependent activation of glucose transport in fat cells. This event is thought to involve vesicle movement from an int...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00361a031
更新日期:1986-07-01 00:00:00
abstract::The bacterial phosphotriesterase (PTE) from Pseudomonas diminuta catalyzes the hydrolysis of organophosphate esters at rates close to the diffusion limit. X-ray diffraction studies have shown that a binuclear metal center is positioned in the active site of PTE and that this complex is responsible for the activation o...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi800971v
更新日期:2008-09-09 00:00:00
abstract::Human erythrocyte spectrin prepared from fresh blood is a mixture of different association states. Depending on the manner of preparation, the two-chain dimer or the tetramer predominates. These forms are not in rapid thermodynamic equilibrium. The molecular weight of the dimer by sedimentation and diffusion and by li...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00644a028
更新日期:1977-12-13 00:00:00
abstract::Distinct structural features of DNA, such as the curvature of dA tracts, are important in the recognition, packaging, and regulation of DNA. Physiologically relevant concentrations of magnesium have been found to enhance the curvature of dA tract DNAs, as monitored by solution-state NMR, indicating that the structure ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi010853j
更新日期:2001-08-07 00:00:00
abstract::Molecular dynamics (MD) simulations of Thermus thermophilus chorismate mutase substrate complex (TtCM x S) have been carried out at 298 K, 333 K, and the temperature of optimum activity: 343 K. The enzyme exists as trimeric subunits with active sites shared between two neighboring subunits. Two features distinguish in...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0604227
更新日期:2006-07-18 00:00:00
abstract::To investigate a conformational change accompanying peptide binding to class II MHC proteins, we probed the structure of a soluble version of the human class II MHC protein HLA-DR1 in empty and peptide-loaded forms. Peptide binding induced a large decrease in the effective radius of the protein as determined by gel fi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi983048m
更新日期:1999-05-04 00:00:00
abstract::The thermal dependence of the structural stability of membrane-reconstituted yeast cytochrome c oxidase has been studied by using different techniques including high-sensitivity differential scanning calorimetry, differential detergent solubility thermal gel analysis, and enzyme activity measurements. For these studie...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00455a028
更新日期:1990-01-23 00:00:00
abstract::A wide variety of biological processes including differentiation, regeneration, and cancer progression are regulated by shedding of membrane-anchored proteins. One of the major sheddases is A Disintegrin And Metalloprotease-17 (ADAM17) whose extracellular region consists of a pro-, a catalytic, a disintegrin-, and a m...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.5b00497
更新日期:2015-09-29 00:00:00
abstract::The understanding of interactions between small molecules and DNA is crucial to design new anticancer drugs targeted to DNA. Methylene blue (MB) is a phenothiazinium dye that has shown promising results in photodynamic therapy treatment. The noncovalent binding of methylene blue to DNA was experimentally and theoretic...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi500068z
更新日期:2014-04-15 00:00:00
abstract::The enzymes in the alpha-ketoglutarate (alphaKG) dependent dioxygenase superfamily represent the largest class of non-heme iron oxidases and have important medical, ecological, and biotechnological roles. One such enzyme, taurine/alpha-ketoglutarate dioxygenase (TauD), catalyzes the conversion of 2-aminoethanesulfonat...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0341096
更新日期:2003-05-20 00:00:00
abstract::Nitrobenzamido ligands linked to the DNA intercalator 9-aminoacridine via poly(methylene) chains induce single-strand nicks in DNA upon irradiation with long-wavelength ultraviolet light (lambda greater than or equal to 300 nm). Optimal photocleavage activity was found for the reagent 9-[[6-(4-nitrobenzamido)hexyl]ami...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00417a021
更新日期:1988-08-23 00:00:00
abstract::Pepstatin is a slow and tight-binding inhibitor of pepsin. Preincubating enzyme and inhibitor in H2O and in D2O in the absence of substrate generates an inverse solvent isotope effect of Dk = 0.69 +/- 0.06 on the apparent first-order rate constant for the decay in enzymatic activity. Proton inventory analysis of the i...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00198a032
更新日期:1994-08-16 00:00:00
abstract::The borrelidin polyketide synthase (PKS) begins with a carboxylated substrate and, unlike typical decarboxylative loading PKSs, retains the carboxy group in the final product. The specificity and tolerance of incorporation of carboxyacyl substrate into type I PKSs have not been explored. Here, we show that the first e...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi500951c
更新日期:2014-09-30 00:00:00
abstract::tRNA-guanine transglycosylase (TGT) is a key enzyme involved in the post-transcriptional modification of certain tRNAs in their anticodon wobble positions with queuine. To maintain the correct Watson-Crick base pairing properties of the wobble base (and hence proper translation of the genetic code), TGT must recognize...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi051863d
更新日期:2006-01-17 00:00:00
abstract::To understand the role of disulfide bridges in protein stability, the thermodynamic changes in the denaturation of two mutant human lysozymes lacking a disulfide bridge between Cys-77 and Cys-95 (C77A and C77/95A) were analyzed using differential scanning calorimetry (DSC). At pH 3.0 and 57 degrees C, the stabilities ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00150a028
更新日期:1992-09-08 00:00:00
abstract::The interaction of serine protease (esterases) with 6-chloro-2-pyrones was investigated. Time-dependent inactivation of chymotrypsin, alpha-lytic protease, pig liver elastase, and cholinesterase was found with 3- and 5-benzyl-6-chloro-2-pyrone, as well as 3- and 5-methyl-6-chloro-2-pyrone. No inactivation was observed...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00282a034
更新日期:1983-06-21 00:00:00