Abstract：
:Ornithine decarboxylase (ODC) catalyzes the first committed step in the biosynthesis of polyamines, and it has been identified as a drug target for the treatment of African sleeping sickness, caused by Trypanosoma brucei. ODC is a pyridoxal 5'-phosphate (PLP) dependent enzyme and an obligate homodimer. X-ray structural analysis of the complex of the T. brucei wild-type enzyme with the product putrescine reveals two structural changes that occur upon ligand binding: Lys-69 is displaced by putrescine and forms new interactions with Glu-94 and Asp-88, and the side chain of Cys-360 rotates into the active site to within 3.4 A of the imine bond. Mutation of Cys-360 to Ala or Ser reduces the k(cat) of the decarboxylation reaction by 50- and 1000-fold, respectively. However, HPLC analysis of the products demonstrates that the mutant enzymes almost exclusively catalyze a decarboxylation-dependent transamination reaction to form pyridoxamine 5-phosphate (PMP) and gamma-aminobutyraldehyde, instead of PLP and putrescine. This side reaction arises when the decarboxylated substrate intermediate is protonated at C4' of PLP instead of at the C(alpha) of substrate. For the reaction catalyzed by the wild-type enzyme, this side reaction occurs infrequently (<0.01% of the turnovers). Single turnover analysis and multiwavelength stopped-flow spectroscopic studies suggest that for the mutant ODCs protonation at C4' occurs either very rapidly or in a concerted reaction with decarboxylation and that the rate-limiting step in the steady-state reaction is Schiff base hydrolysis/product release. These studies demonstrate a role for Cys-360 in the control of the C(alpha) protonation step that catalyzes the formation of the physiological product putrescine. The results further provide insight into the mechanism by which this class of PLP-dependent enzymes controls reaction specificity.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Jackson LK,Brooks HB,Osterman AL,Goldsmith EJ,Phillips MAdoi
10.1021/bi001209ssubject
Has Abstractpub_date
2000-09-19 00:00:00pages
11247-57issue
37eissn
0006-2960issn
1520-4995pii
bi001209sjournal_volume
39pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract：:We have performed microsecond (μs) molecular dynamics simulation (MDS) to identify structural mechanisms for sarcolipin (SLN) uncoupling of Ca2+ transport from ATP hydrolysis for the sarcoplasmic reticulum Ca2+-ATPase (SERCA). SLN regulates muscle metabolism and energy expenditure to provide resistance against diet-in...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/acs.biochem.6b00728
更新日期：2016-11-08 00:00:00
abstract：:Aromatic amine dehydrogenase (AADH) is the second enzyme known to possess the tryptophan tryptophylquinone (TTQ) prosthetic group. Its ability to catalyze the oxidative deamination of a wide range of aromatic and aliphatic amines has been investigated. Steady-state and transient kinetic studies of the reaction of AADH...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00003a015
更新日期：1995-01-24 00:00:00
abstract：:The fluorescence intensity of the two flavin prosthetic groups, FMN and FAD, in neuronal nitric oxide synthase (nNOS) was found to decay highly nonexponentially, being best described by four fluorescence lifetimes. This excited state heterogeneity is the result of multiple flavin quenching sites which are due to sever...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi981138l
更新日期：1998-12-15 00:00:00
abstract：:Binding of 125I-labeled human alpha-thrombin to endothelial cells derived from bovine corneas was studied in tissue culture. Specific and saturable binding to the cell surface occurred at 37 degrees C but to a much smaller extent at 4 degrees C. Binding of [125I]thrombin to a specific site on these cells with formatio...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00505a027
更新日期：1981-01-20 00:00:00
abstract：:Guanidinium chloride- (GdmCl-) induced unfolding of beta-lactamase has been investigated by a combination of size-exclusion chromatography (SEC-FPLC) and usual optical methods. It has been shown that at low temperatures this protein unfolds through two equilibrium intermediates. The first of these intermediates is the...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00176a006
更新日期：1994-03-15 00:00:00
abstract：:The synthesis of 5-(2-oxalylethyl)-NADH, a reduced nicotinamide adenine dinucleotide (NADH) derivate with pyruvate covalently attached to the 5 position of the dihydronicotinamide ring over an additional methylene group has been described previously (Trommer, W.E., Blume, H., and Kapmeyer, H. (1976) Justus Liebigs Ann...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00668a012
更新日期：1976-11-16 00:00:00
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：:To maintain daily cycles, the circadian clock must tightly regulate the rhythms of thousands of mRNAs and proteins with the correct period, phase, and amplitude to ultimately drive the wide range of rhythmic biological processes. Recent genomic approaches have revolutionized our view of circadian gene expression and h...
journal_title：Biochemistry
pub_type： 杂志文章,评审
doi：10.1021/bi500707c
更新日期：2015-01-20 00:00:00
abstract：:The beta(2) subunit of a class Ia or Ib ribonucleotide reductase (RNR) is activated when its carboxylate-bridged Fe(2)(II/II) cluster reacts with O(2) to oxidize a nearby tyrosine (Y) residue to a stable radical (Y(*)). During turnover, the Y(*) in beta(2) is thought to reversibly oxidize a cysteine (C) in the alpha(2...
journal_title：Biochemistry
pub_type： 杂志文章,评审
doi：10.1021/bi8017625
更新日期：2008-12-30 00:00:00
abstract：:The apolipoproteins of insect lipophorin were dissociated in guanidinium chloride and isolated by gel permeation chromatography. Over 98% of the total lipid in lipophorin was associated with apolipophorin I (apoLp-I), thus suggesting this apolipoprotein to be the lipid binding component of the particle. ApoLp-I was de...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00442a019
更新日期：1989-08-08 00:00:00
abstract：:The acid-induced arginine decarboxylase is part of an enzymatic system in Escherichia coli that contributes to making this organism acid resistant. The arginine decarboxylase is a vitamin B(6)-dependent enzyme that is active at acidic pH. It consumes a proton in the decarboxylation of arginine to agmatine, and by work...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi900075d
更新日期：2009-05-12 00:00:00
abstract：:The conformations of three peptide models of the one-disulfide and fully reduced forms of apamin were characterized by using nuclear magnetic resonance (NMR) spectroscopy. Apa-2 contains the native disulfide bond between Cys3 and Cys15 in apamin with the other two cysteines replaced by alanines. Apa-1 contains the nat...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00183a031
更新日期：1994-05-03 00:00:00
abstract：:Total internal reflection fluorescence microscopy (TIRFM) has been used to directly measure the weak dissociation constants of IgG with a mouse IgG receptor (moFc gamma RII) that has been purified and reconstituted into substrate-supported planar membranes. Dissociation constants were measured for three different mous...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00161a039
更新日期：1992-11-24 00:00:00
abstract：:The effect on overall alpha-helix content of substituting proline for alanine has been determined at 5 positions (1, 2, 4, 5, and 13) of a 13-residue peptide related in sequence to residues 1-13 of ribonuclease A. The helix content falls off rapidly as proline is moved inward, and the proline residue effectively trunc...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00237a026
更新日期：1991-06-11 00:00:00
abstract：:The bond cleavage step of pepsinogen activation has been investigated in a kinetic study in which the denatured products of short-term acidifications were separated on SDS-polyacrylamide gels and the peptide products were quantitated by densitometry. Although several peptide products were observed, under the condition...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00432a040
更新日期：1989-03-21 00:00:00
abstract：:It is known that the proapoptotic protein Bax facilitates the formation of pores in bilayers, resulting in the release of proteins from the intermitochondrial space. We demonstrate that another consequence of the interaction of Bax with membranes is an increase in the rate of lipid transbilayer diffusion. We use two i...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi035348w
更新日期：2003-12-16 00:00:00
abstract：:The existence of temperature optima in enzyme catalysis that occur before protein melting sets in can be described by different types of kinetic models. Such optima cause distinctly curved Arrhenius plots and have, for example, been observed in several cold-adapted enzymes from psychrophilic species. The two main expl...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/acs.biochem.0c00705
更新日期：2020-10-13 00:00:00
abstract：:The 86-amino acid colicin E9 immunity protein (Im9), which inhibits the DNase activity of colicin E9, has been overexpressed in Escherichia coli and isotopically enriched with 15N and 13C. Using the 3D CBCANH and CBCA(CO)NH experiments, we have almost completely assigned the backbone 13C resonances and extended previo...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi960401k
更新日期：1996-07-23 00:00:00
abstract：:G protein-coupled receptor (GPCR) kinases (GRKs) instigate the desensitization of activated GPCRs via phosphorylation that promotes interaction with arrestins, thereby preventing the interaction of GPCRs with heterotrimeric G proteins. A current proposed model of GRK1 activation involves the binding of activated rhodo...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi300295y
更新日期：2012-04-24 00:00:00
abstract：:Streptococcus pneumoniae 5'-methylthioadenosine/S-adenosylhomocysteine hydrolase (MTAN) catalyzes the hydrolytic deadenylation of its substrates to form adenine and 5-methylthioribose or S-ribosylhomocysteine (SRH). MTAN is not found in mammals but is involved in bacterial quorum sensing. MTAN gene disruption affects ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi061184i
更新日期：2006-10-31 00:00:00
abstract：:Azurin from Pseudomonas aeruginosa and two mutants where the methionine ligand has been mutated have been studied in order to directly investigate the functional and structural significance of this ligand in the blue copper proteins. Reduction potentials, X-ray absorption fine structure (XAFS), electron paramagnetic r...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00059a013
更新日期：1993-03-02 00:00:00
abstract：:Raman spectra of phycocyanobilin, phycocyanin, and allophycocyanin were obtained at resonance with their visible and near-UV transitions. These spectra were empirically assigned with the help of 14N- and 15N-isotopic substitutions and comparisons with resonance Raman spectra of phycoerythrin. These results confirm the...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00205a019
更新日期：1994-10-04 00:00:00
abstract：:Human NFU (also known as HIRIP5) has been implicated in cellular iron-sulfur cluster biosynthesis. Bacterial and yeast forms are smaller than the human protein and are homologous to the C-terminal domain of the latter. This C-terminal domain contains a pair of redox active cysteines and demonstrates thioredoxin-like a...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi801645z
更新日期：2009-02-10 00:00:00
abstract：:Biochemical and immunological properties of biosynthetically radiolabeled phosphatidylcholine-(PC-) binding proteins were investigated. The PC-binding proteins were extracted from the detergent lysate of biosynthetically radiolabeled P388D1 cells by affinity chromatography on PC-Sepharose and filtered through a Sephad...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00329a014
更新日期：1985-04-09 00:00:00
abstract：:In eukaryotic organisms, the largely cytosolic copper- and zinc-containing superoxide dismutase (Cu/Zn SOD) enzyme represents a key defense against reactive oxygen toxicity. Although much is known about the biology of this enzyme under aerobic conditions, less is understood regarding the effects of low oxygen levels o...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi201353y
更新日期：2012-01-17 00:00:00
abstract：:Previous studies have shown that protein 4.1 is a multifunctional protein that binds to spectrin, actin, glycophorins, the anion channel protein, and phosphatidylserine (PS). In this report, we have characterized the binding of protein 4.1 and its major proteolytic fragments to phospholipid vesicles. Pure 125I-labeled...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00402a018
更新日期：1988-01-26 00:00:00
abstract：:The rapid expansion of the amount of genomic and structural data has provided many examples of enzymes with evolutionarily related active sites that catalyze different reactions. Functional comparisons of these active sites can provide insight into the origins of the enormous catalytic proficiency of enzymes and the e...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi060847t
更新日期：2006-08-15 00:00:00
abstract：:The dependence of the activity of recombinant activated human protein C (r-APC) on each of its nine gamma-carboxyglutamic (Gla) residues (sequence positions 6, 7, 14, 16, 19, 20, 25, 26, and 29) has been assessed in purified systems and in plasma using r-mutants in which each Gla residue of r-APC was individually alte...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00173a033
更新日期：1994-02-22 00:00:00
abstract：:A fluorescence quenching method was developed for determining partition coefficients and diffusional rates of small molecules in cell membranes. This method involves quenching the fluorescence of carbazole-labeled membranes by hydrophobic molecules that partition into membranes. Cell membrane phospholipids of mouse LM...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00316a021
更新日期：1984-10-09 00:00:00
abstract：:Three sites of N(G),N(G)-arginine methylation have been located at residues 205, 217, and 224 in the glycine-rich, COOH-terminal one-third of the HeLa A1 heterogeneous ribonucleoprotein. Together with the previously determined dimethylated arginine at position 193 [Williams et al., (1985) Proc. Natl. Acad. Sci. U.S.A....
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi9625509
更新日期：1997-04-29 00:00:00
