Maturating enzyme

Arecombinant streptococcalC5apeptidasewas expressed in Escherichia coliand its catalytic properties and thermal sta-bility were subjected to examination. It was shown that the NH2 -terminal region ofC5a peptidase (Asn32–Asp79/ Lys90) forms the pro-sequence segment. Upon maturation the propeptide is hydrolyzed either via an autocatalytic intramolecular cleavage or by exogenous protease strepto-pain. At pH 7.4 the enzyme exhibited maximum activity in the narrow range oftemperatures between 40 and 43
C....

13p research12 29-04-2013 46 3   Download

Genes homologous to hydrogenase accessory genes are scattered over the whole genome in the cyanobacteriumSynechocystissp. PCC 6803. Deletion and insertion mutants of hypA1 (slr1675), hypB1 (sll1432), hypC, hypD, hypE and hypF were constructed and showed no hydrogenase activity. Involvement of the respective genes in maturation of the enzyme was con-firmed by complementation. Deletion of the additional homologueshypA2 (sll1078) and hypB2(sll1079) had no effect on hydrogenase activity. Thus, hypA1andhypB1are specific for hydrogenase maturation....

12p tumor12 20-04-2013 31 4   Download

Mature, active mammalian histidine decarboxylase is a di-meric enzyme of carboxy-truncatedmonomers (
53 kDa). By using a biocomputational approach, we have generateda three-dimensional model of a recombinant 1/512 fragment of the rat enzyme, which shows kinetic constants similar to those of the mature enzyme purified from rodent tissues. This model, together with previous spectroscopic data, al-lowed us to postulate that the occupation of the catalytic center by the natural substrate, or by substrate-analogs, would induce remarkable changes in the conformation of the intact holoenzyme....

12p tumor12 20-04-2013 36 2   Download

Transglutaminase (TGase) fromStreptomyces mobaraensis is secreted as a precursor protein which is completely acti-vated by the endoprotease TAMEP, a member of the M4 protease family [Zotzel, J., Keller, P. & Fuchsbauer, H.-L. (2003) Eur. J. Biochem. 270, 3214–3222]. In contrast with the mature enzyme, TAMEP-activated TGase exhibits an additional N-terminal tetrapeptide (Phe-Arg-Ala-Pro) sug-gesting truncation, at least, by a second protease.

7p tumor12 20-04-2013 49 1   Download

We purified pancreatic deoxyribonucleases I (DNases I) from three snakes, Elaphe quadrivirgata, Elaphe climaco-phoraandAgkistrodon blomhoffii, and cloned their cDNAs. Each mature snake DNase I protein comprised 262 amino acids. Wild-type snake DNases I with Leu130 were more thermally unstable than wild-type mammalian and avian DNases I with Ile130. After substitution of Leu130Ile, the thermal stabilities of the snake enzymes were higher than those of their wild-type counterparts and similar to mam-malian wild-type enzyme levels....

8p tumor12 20-04-2013 41 3   Download

Pest insects such asHelicoverpaspp. frequently feed on plants expressing protease inhibitors. Apparently, their digestive system can adapt to the presence of protease inhibitors. To study this, a trypsin enzymewas purified from the gut of insects that were raised on an inhibitor-containing diet. The amino-acid sequence of this enzyme was analysed by tandem MS, which allowed assignment of 66% of the mature protein amino acid sequence. This trypsin, called HzTrypsin-S, corresponded to a known cDNA sequence fromHelicoverpa. ...

10p tumor12 20-04-2013 26 3   Download

Tumor necrosis factor-a converting enzyme (TACE or ADAM17) is a member of the ADAM (a disintegrin and metalloproteinase) family of type I membrane proteins and mediates the ectodomain shedding of various membrane-anchored signaling and adhesion proteins. TACE is syn-thesized as an inactive zymogen, which is subsequently proteolytically processed to the catalytically active form.We have identified the proprotein-convertases PC7 and furin to be involved in maturation of TACE.

8p fptmusic 16-04-2013 37 3   Download

Penicillin amidase fromAlcaligenes faecalisis a recently identifiedN-terminal nucleophilehydrolase,whichpossesses the highest specificity constant (kcat /Km)forthehydrolysis of benzylpenicillin compared with penicillin amidases from other sources. Similar to theEscherichia colipenicillin ami-dase, theA. faecalispenicillin amidase is maturatedin vivo from an inactive precursor into the catalytically active enzyme, containing one tightly bound Ca 2+ ion, via a complex post-translational autocatalytic processing with a multi-step excision of a small internal pro-peptide. ...

8p fptmusic 12-04-2013 54 4   Download

Two cDNA homologues of medaka hatching enzyme)high choriolytic enzyme (HCE) and low choriolytic enzyme (LCE) – were cloned from Fundulus heteroclitusembryos. Amino acid sequences of the mature forms ofFundulusHCE (FHCE) and LCE (FLCE) were 77.9% and 63.3% iden-tical to those of medaka HCE and LCE, respectively. In addition, phylo-genetic analysis clearly showed that FHCE and FLCE belonged to the clades of HCE and LCE, respectively.

12p fptmusic 11-04-2013 54 3   Download

The highly conserved, atypical RIO serine protein kinases are found in all organisms, from archaea to man. In yeast, the kinase activity of Rio2 is necessary for the final processing step of maturing the 18S ribosomal rRNA. We have previously shown that the Rio2 protein from Archaeo-globus fulgidus contains both a small kinase domain and an N-terminal winged helix domain.

0p awards 06-04-2013 41 3   Download

The gene encompassing ORF Rv1885c with weak sequence similarity to AroQ chorismate mutases (CMs) was cloned from the genome ofMycobac-terium tuberculosis and expressed in Escherichia coli. The gene product (*MtCM) complements a CM-deficient E. colistrain, but only if produced without the predicted N-terminal signal sequence typical ofM. tuberculosis. The mature *MtCM, which was purified by exploiting its resistance to irre-versible thermal denaturation, possesses high CM activity in vitro.

15p awards 05-04-2013 36 2   Download

Many organelle enzymes coded for by nuclear genes have N-terminal sequences, which directs them into the organelle (precursor) and are removed upon import (mature). The experiments described below charac-terize the differences between the precursor and mature forms of water-melon glyoxysomal malate dehydrogenase. Using recombinant protein methods, the precursor (p-gMDH) and mature (gMDH) forms were puri-fied to homogeneity using Ni 2+ –NTA affinity chromatography.

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HIV-1 protease is a pivotal enzyme in the later stages of the viral life cycle which is responsible for the processing and maturation of the virus particle into an infectious virion. As such,HIV-1proteasehasbecomean important target for the treatment ofAIDS, and efficient drugs have beendeveloped. However, negative side effects and fast emerging resistance to the current drugs have necessitated the development of novel chemical entities in order to exploit different phar-macokinetic properties as well as new interaction patterns....

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Two chloroplast phosphoglycerate kinase isoforms fromthe photosynthetic flagellateEuglena graciliswere purified to homogeneity, partially sequenced, and subsequently cDNAs encoding phosphoglycerate kinase isoenzymes from both the chloroplast and cytosol of E. graciliswere cloned and sequenced. Chloroplast phosphoglycerate kinase, a mono-meric enzyme, was encoded as a polyprotein precursor of at least four mature subunits that were separated by conserved tetrapeptides.

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TheCPBgenes of the protozoan parasiteLeishmania mex-icana encode stage-regulated cathepsin L-like cysteine pro-teases that are important virulence factors and are in a tandem array of 19 genes. In this study, we have compared the substrate preferences of two CPB isoforms, CPB2.8 and CPB3, and a H84Y mutant of the latter enzyme, to analyse the roles played by the few amino acid differences between the isoenzymes in determining substrate specificity. CPB3 differs fromCPB2.8 at just three residues (N60D,D61Nand D64S) in the mature domain. ...

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Aspartic proteinases of the A1 family are widely distributed among plant species and have been purified from a variety of tissues. They are most active at acidic pH, are specifically inhibited by pepstatin A and contain two aspartic residues indispensible for catalytic activity. The three-dimensional structure of two plant aspartic proteinases has been deter-mined, sharing significant structural similarity with other known structures of mammalian aspartic proteinases.

9p dell39 03-04-2013 33 3   Download

MicroRNAs (miRNAs) are generated from primary transcripts through sequential processing by two RNase III enzymes, Drosha and Dicer, in association with other proteins. This maturation is essential for their func-tion as post-transcriptional regulators.

8p media19 06-03-2013 25 2   Download

l-Glutamate oxidase (LGOX) from Streptomycessp. X-119-6, which cata-lyzes the oxidative deamination of l-glutamate, has attracted increasing attention as a component of amperometricl-glutamate sensors used in the food industry and clinical biochemistry. The precursor of LGOX, which has a homodimeric structure, is less active than the mature enzyme with an a2b2c2 structure;

10p vinaphone15 25-02-2013 51 4   Download

The C-terminus of the fungal laccase fromMelanocarpus albomyces(MaL) is processed during secretion at a processing site conserved among the ascomycete laccases. The three-dimensional structure of MaL has been solved as one of the first complete laccase structures. According to the crystal structure of MaL, the four C-terminal amino acids of the mature protein penetrate into a tunnel leading towards the trinuclear site.

16p viettel02 20-02-2013 49 3   Download

Sulfatases form a major group of enzymes present in prokaryotes and eukaryotes. This class of hydrolases is unique in requiring essential post-translational modification of a critical active-site cysteinyl or seryl residue to Ca-formylglycine (FGly).

15p mobifone23 21-01-2013 42 4   Download