Abstract:
:Monomeric sarcosine oxidase (MSOX) binds the L-proline zwitterion (pKa = 10.6). The reactive substrate anion is generated by ionization of the ES complex (pKa = 8.0). Tyr317 was mutated to Phe to determine whether this step might involve proton transfer to an active site base. The mutation does not eliminate the ionizable group in the ES complex (pKa = 8.9) but does cause a 20-fold decrease in the maximum rate of the reductive half-reaction. Kinetically determined Kd values for the ES complex formed with L-proline agree with results obtained in spectral titrations with the wild-type or mutant enzyme. Unlike the wild-type enzyme, Kd values with the mutant enzyme are pH-dependent, suggesting that the mutation has perturbed the pKa of a group that affects the Kd. As compared with the wild-type enzyme, an increase in charge transfer band energy is observed for mutant enzyme complexes with substrate analogues while a 10-fold decrease in the charge transfer band extinction coefficient is found for the complex with the L-proline anion. The results eliminate Tyr317 as a possible acceptor of the proton released upon substrate ionization. Since previous studies rule out the only other nearby base, we conclude that L-proline is the ionizable group in the ES complex and that amino acids are activated for oxidation upon binding to MSOX by stabilization of the reactive substrate anion. Tyr317 may play a role in substrate activation and optimizing binding, as judged by the effects of its mutation on the observed pKa, reaction rates, and charge transfer bands.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Zhao G,Jorns MSdoi
10.1021/bi051898dsubject
Has Abstractpub_date
2005-12-27 00:00:00pages
16866-74issue
51eissn
0006-2960issn
1520-4995journal_volume
44pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::Despite many studies suggesting the role of enolpyruvate as a bound intermediate in the pyruvate kinase reaction, direct evidence for it has been lacking. By use of a combination of chemical trapping and isolation of a derivative, significant amounts of enzyme-bound enolpyruvate have now been demonstrated. The method ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00217a022
更新日期:1991-01-22 00:00:00
abstract::The heterodimeric actin capping protein (CP) is regulated by a set of proteins that contain CP-interacting (CPI) motifs. Outside of the CPI motif, the sequences of these proteins are unrelated and distinct. The CPI motif and surrounding sequences are conserved within a given protein family, when compared to those of o...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.0c00092
更新日期:2020-03-24 00:00:00
abstract::The bacterial phosphoenolpyruvate:sugar phosphotransferase system involves a series of reactions in which phosphoprotein intermediates are formed. Histidine-containing protein (HPr) is phosphorylated on the N delta 1 position of the imidazole ring of His15 by enzyme I and acts as a phosphoryl donor to the sugar-specif...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00255a008
更新日期:1994-12-27 00:00:00
abstract::The crystal structure of fiddler crab collagenase complexed with the dimeric serine protease inhibitor ecotin at 2.5 A resolution reveals an extended cleft providing binding sites for at least 11 contiguous substrate residues. Comparison of the positions of nine intermolecular main chain hydrogen bonding interactions ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9617522
更新日期:1997-05-06 00:00:00
abstract::Cyanobacteriochromes (CBCRs) are photosensory proteins related to the red/far-red phytochromes. Like phytochromes, CBCRs use linear tetrapyrrole (bilin) chromophores covalently attached via a thioether linkage to a conserved Cys residue also found in plant and cyanobacterial phytochromes. Unlike almost all phytochrome...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi300171s
更新日期:2012-05-01 00:00:00
abstract::Resonance Raman spectra of the photosynthetic reaction center isolated from the green bacterium Chloroflexus aurantiacus have been obtained with excitation in the near-infrared absorption bands of the special pair (P) and the accessory bacteriochlorophyll (B) using shifted-excitation Raman difference spectroscopy (SER...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00015a044
更新日期:1995-04-18 00:00:00
abstract::R67 dihydrofolate reductase (DHFR), which catalyzes the NADPH dependent reduction of dihydrofolate to tetrahydrofolate, belongs to a type II family of R-plasmid encoded DHFRs that confer resistance to the antibacterial drug trimethoprim. Crystal structure data reveals this enzyme is a homotetramer that possesses a sin...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi034643d
更新日期:2003-09-16 00:00:00
abstract::Human immunodeficiency virus type 1 (HIV-1) Vpu is an integral membrane protein that belongs to the viroporin family. Viroporins interact with cell membranes, triggering membrane permeabilization and promoting release of viral particles. In vitro electrophysiological methods have revealed changes in membrane ion curre...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi3011175
更新日期:2013-01-08 00:00:00
abstract::Identical first-order rate constants for phosphorylation of the calcium ATPase of sarcoplasmic reticulum by bound inorganic phosphate (Pi) of 25 +/- 2 s-1 with empty vesicles and 25 +/- 1 s-1 with vesicles that were passively loaded with 40 mM Ca2+ were obtained by treating the reaction as an approach to equilibrium (...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00009a039
更新日期:1995-03-07 00:00:00
abstract::A fluorescence method is presented for quantitatively analyzing exocytosis phenomena and monitoring their kinetics. The method is based on the particular properties of a hydrophobic fluorescent probe, 1-[4-(trimethylammonio)phenyl]-6-phenylhexa-1,3,5-triene (TMA-DPH) [Prendergast, F.G., Haugland, R.P., & Callahan, P.J...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00356a045
更新日期:1986-04-22 00:00:00
abstract::Cytochrome c-553 from Desulfovibrio vulgaris exhibits a highly exposed heme and an unusually low reduction potential with respect to other c-type cytochromes. Solvent heme exposure has been indicated as one of the most important factors in modulating the midpoint potential of the redox center. To test this hypothesis,...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi025759x
更新日期:2002-07-09 00:00:00
abstract::The Radical SAM (RS) enzyme PqqE catalyzes the first step in the biosynthesis of the bacterial cofactor pyrroloquinoline quinone, forming a new carbon-carbon bond between two side chains within the ribosomally synthesized peptide substrate PqqA. In addition to the active site RS 4Fe-4S cluster, PqqE is predicted to ha...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.7b01097
更新日期:2018-02-27 00:00:00
abstract::F62 LOS of Neisseria gonorrhoeae consists of two major LOS components; the higher and smaller molecular weight (MW) components were recognized by MAbs 1-1-M and 3F11 respectively. Base-line separation of the two major oligosaccharide (OS) components from F62 LOS was achieved by Bio-Gel P-4 chromatography after dephosp...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00107a028
更新日期:1991-10-29 00:00:00
abstract::The solution structure of the complementary d(C1-A2-T3-G4-X5-G6-T7-A8-C9).d(G10-T11-A12-C13-A14-C15-A16-T17-G18) DNA duplex (designated X.A 9-mer), which contains a 1,N2-propanodeoxyguanosine exocyclic adduct X5 opposite deoxyadenosine A14 at the center, is pH dependent [Kouchakdjian, M., Eisenberg, M., Live, D., Mari...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00066a004
更新日期:1993-04-20 00:00:00
abstract::Members of the ATP-binding cassette (ABC) transporters share the same basic architecture, with a four-core domain made of two transmembrane plus two nucleotide-binding domains. However, a supramolecular organization has been detected in some ABC transporters, which might be relevant to physiological regulation of subs...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0482809
更新日期:2005-03-22 00:00:00
abstract::The plasma membrane serotonin transporter (SERT) has an important role in terminating serotonergic neurotransmission by re-uptake of 5-HT from the synaptic cleft. The expression of SERT on the cell surface is therefore a critical factor. In this study, we examined the role of the carboxyl terminus of SERT in trafficki...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0508688
更新日期:2006-01-31 00:00:00
abstract::The rates of inactivation of BF1 adenosinetriphosphatase (BF1-ATPase) from Escherichia coli by 7-chloro-4-nitro-2,1,3-benzoxadiazole, 1-fluoro-2,4-dinitrobenzene, 2,4,6-trinitrobenzenesulfonate, phenylglyoxal, and N,N'-dicyclohexylcarbodiimide have been measured in the presence and absence of various concentrations of...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00531a011
更新日期:1982-01-19 00:00:00
abstract::The 24-kDa subunit of mitochondrial NADH-ubiquinone reductase (complex I) is an iron-sulfur protein that is present in the flavoprotein or NADH dehydrogenase II subcomplex. It is a nuclear gene product and is imported into the organelle. A group of human patients with mitochondrial myopathy have been shown to have red...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00434a021
更新日期:1989-04-18 00:00:00
abstract::One of the most promising approaches to anti-hepatitis C virus drug discovery is the development of inhibitors of the virally encoded protease NS3. This chymotrypsin-like serine protease is essential for the maturation of the viral polyprotein, and processing requires complex formation between NS3 and its cofactor NS4...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi991220w
更新日期:1999-10-19 00:00:00
abstract::The solution structure of the actinorhodin acyl carrier protein (act apo-ACP) from the polyketide synthase (PKS) of Streptomyces coelicolor A3(2) has been determined using 1H NMR spectroscopy, representing the first polyketide synthase component for which detailed structural information has been obtained. Twenty-four ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi970006+
更新日期:1997-05-20 00:00:00
abstract::His12 and His119 are critical for catalysis of RNA cleavage by ribonuclease A (RNase A). Substitution of either residue with an alanine decreases the value of k(cat)/K(M) by more than 10(4)-fold. His12 and His119 are proximal to the scissile phosphoryl group of an RNA substrate in enzyme-substrate complexes. Here, the...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0100182
更新日期:2001-04-24 00:00:00
abstract::Guanylin, an intestinal peptide hormone and endogenous ligand of guanylyl cyclase C, is produced as the corresponding prohormone proguanylin. The mature hormone consists of 15 amino acid residues, representing the COOH-terminal part of the prohormone comprised of 94 amino acid residues. Here we report the recombinant ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi026434j
更新日期:2002-12-10 00:00:00
abstract::Human erythrocyte band 3 inhibits glycolytic enzymes, including aldolase, by binding these cytoplasmic enzymes at its N-terminus. Phosphorylation of Y8 disrupts inhibition, and there is evidence that in vivo glycolysis levels in erythrocytes are regulated in part by a phosphorylation/dephosphorylation signaling pathwa...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00051a005
更新日期:1995-12-26 00:00:00
abstract::Serine hydroxymethyltransferase and C1-tetrahydrofolate synthase catalyze four reactions which convert formate and glycine to serine. The one-carbon carrier in these reactions if tetrahydropteroylglutamate which is regenerated in the coupled reaction and thus can be used in catalytic concentrations with respect to ser...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00450a028
更新日期:1989-11-28 00:00:00
abstract::Proton-detected heteronuclear multiple-bond 1H-13C correlations (HMBC) previously have been used for assignment purposes in a variety of isotopically enriched proteins. In the present study it is demonstrated that the technique yields an almost complete assignment of the natural abundance 13C spectrum of the protein b...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00107a014
更新日期:1991-10-29 00:00:00
abstract::Bacteriophage T7 codes for a single-stranded DNA binding protein. This protein is the product of gene 2.5 and has been found previously to stimulate specifically the activity of the phage-coded DNA polymerase. We report here that the T7 DNA binding protein also stimulates the activity of the phage-coded exonuclease. T...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00266a042
更新日期:1982-11-09 00:00:00
abstract::Nitrophorins 1-4 (NP1-4) are ferriheme proteins from the blood-sucking insect Rhodnius prolixus that transport nitric oxide (NO) to the victim, sequester histamine, and inhibit blood coagulation. Here, we report kinetic and thermodynamic analyses for ligand binding by all four proteins and their reduction potentials. ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi000766b
更新日期:2000-08-22 00:00:00
abstract::myo-Inositol (mI) is widely distributed in all domains of life and is important for several cellular functions, including bacterial survival. The enzymes responsible for the bacterial catabolism of mI, encoded in the iol operon, can vary from one organism to another, and these pathways have yet to be fully characteriz...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.0c00539
更新日期:2020-08-18 00:00:00
abstract::Glucose oxidation to CO2 was investigated in isolated perifused rat epididymal fat cells. Insulin stimulated rates of oxidation up to 30-fold. Multiple pulses of insulin or prolonged perifusion with the hormone led to a time-dependent desensitization of the cells. The action of insulin could be mimicked by H2O2. Rever...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00273a013
更新日期:1983-02-15 00:00:00
abstract::(E)-4-Hydroxy-3-methylbut-2-enyl diphosphate reductase (IspH or LytB) catalyzes the terminal step of the MEP/DOXP pathway where it converts (E)-4-hydroxy-3-methylbut-2-enyl diphosphate (HMBPP) into the two products, isopentenyl diphosphate and dimethylallyl diphosphate. The reaction involves the reductive elimination ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi3001215
更新日期:2012-06-19 00:00:00