scholarly journals Characterization of Native and Recombinant Forms of an Unusual Cobalt-Dependent Proline Dipeptidase (Prolidase) from the Hyperthermophilic Archaeon Pyrococcus furiosus

1998 ◽  
Vol 180 (18) ◽  
pp. 4781-4789 ◽  
Author(s):  
Mousumi Ghosh ◽  
Amy M. Grunden ◽  
Dianne M. Dunn ◽  
Robert Weiss ◽  
Michael W. W. Adams
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Substrate Specificity ◽  
Metal Ion ◽  
Pyrococcus Furiosus ◽  
Cobalt Atom ◽  
Significant Similarity ◽  
Genome Database ◽  
Hyperthermophilic Archaeon ◽  
Cell Extracts

ABSTRACT Proline dipeptidase (prolidase) was purified from cell extracts of the proteolytic, hyperthermophilic archaeon Pyrococcus furiosus by multistep chromatography. The enzyme is a homodimer (39.4 kDa per subunit) and as purified contains one cobalt atom per subunit. Its catalytic activity also required the addition of Co2+ ions (Kd , 0.24 mM), indicating that the enzyme has a second metal ion binding site. Co2+could be replaced by Mn2+ (resulting in a 25% decrease in activity) but not by Mg2+, Ca2+, Fe2+, Zn2+, Cu2+, or Ni2+. The prolidase exhibited a narrow substrate specificity and hydrolyzed only dipeptides with proline at the C terminus and a nonpolar amino acid (Met, Leu, Val, Phe, or Ala) at the N terminus. Optimal prolidase activity with Met-Pro as the substrate occurred at a pH of 7.0 and a temperature of 100°C. The N-terminal amino acid sequence of the purified prolidase was used to identify in the P. furiosus genome database a putative prolidase-encoding gene with a product corresponding to 349 amino acids. This gene was expressed in Escherichia coli and the recombinant protein was purified. Its properties, including molecular mass, metal ion dependence, pH and temperature optima, substrate specificity, and thermostability, were indistinguishable from those of the native prolidase from P. furiosus. Furthermore, theKm values for the substrate Met-Pro were comparable for the native and recombinant forms, although the recombinant enzyme exhibited a twofold greaterV max value than the native protein. The amino acid sequence of P. furiosus prolidase has significant similarity with those of prolidases from mesophilic organisms, but the enzyme differs from them in its substrate specificity, thermostability, metal dependency, and response to inhibitors. The P. furiosus enzyme appears to be the second Co-containing member (after methionine aminopeptidase) of the binuclear N-terminal exopeptidase family.

scholarly journals Characterization of a Novel Zinc-Containing, Lysine-Specific Aminopeptidase from the Hyperthermophilic Archaeon Pyrococcus furiosus

2005 ◽  
Vol 187 (6) ◽  
pp. 2077-2083 ◽  
Author(s):  
Sherry V. Story ◽  
Claudia Shah ◽  
Francis E. Jenney ◽  
Michael W. W. Adams
Keyword(s):  
Metal Ion ◽  
Specific Activity ◽  
Pyrococcus Furiosus ◽  
High Specific Activity ◽  
Native Form ◽  
Genome Database ◽  
Hyperthermophilic Archaeon ◽  
Cell Extracts ◽  
Hydrolysis Of

ABSTRACT Cell extracts of the proteolytic, hyperthermophilic archaeon Pyrococcus furiosus contain high specific activity (11 U/mg) of lysine aminopeptidase (KAP), as measured by the hydrolysis of l-lysyl-p-nitroanilide (Lys-pNA). The enzyme was purified by multistep chromatography. KAP is a homotetramer (38.2 kDa per subunit) and, as purified, contains 2.0 ± 0.48 zinc atoms per subunit. Surprisingly, its activity was stimulated fourfold by the addition of Co2+ ions (0.2 mM). Optimal KAP activity with Lys-pNA as the substrate occurred at pH 8.0 and a temperature of 100°C. The enzyme had a narrow substrate specificity with di-, tri-, and tetrapeptides, and it hydrolyzed only basic N-terminal residues at high rates. Mass spectroscopy analysis of the purified enzyme was used to identify, in the P. furiosus genome database, a gene (PF1861) that encodes a product corresponding to 346 amino acids. The recombinant protein containing a polyhistidine tag at the N terminus was produced in Escherichia coli and purified using affinity chromatography. Its properties, including molecular mass, metal ion dependence, and pH and temperature optima for catalysis, were indistinguishable from those of the native form, although the thermostability of the recombinant form was dramatically lower than that of the native enzyme (half-life of approximately 6 h at 100°C). Based on its amino acid sequence, KAP is part of the M18 family of peptidases and represents the first prokaryotic member of this family. KAP is also the first lysine-specific aminopeptidase to be purified from an archaeon.

scholarly journals Novel Type of Glucose-6-Phosphate Isomerase in the Hyperthermophilic Archaeon Pyrococcus furiosus

2001 ◽  
Vol 183 (11) ◽  
pp. 3428-3435 ◽  
Author(s):  
Thomas Hansen ◽  
Margitta Oehlmann ◽  
Peter Schönheit
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Physiological Function ◽  
Pyrococcus Furiosus ◽  
Single Type ◽  
Kinetic Properties ◽  
Significant Similarity ◽  
Reading Frame ◽  
Hyperthermophilic Archaeon ◽  
Terminal Amino

ABSTRACT Glucose-6-phosphate isomerase (phosphoglucose isomerase [PGI]) (EC 5.3.1.9 ) from the hyperthermophilic archaeon Pyrococcus furiosus was purified 500-fold to homogeneity. The enzyme had an apparent molecular mass of 43 kDa and was composed of a single type of subunit of 23 kDa indicating a homodimeric (α2) structure. Kinetic constants of the enzyme were determined at the optimal pH 7 and at 80°C. Rate dependence on both substrates followed Michaelis-Menten kinetics. The apparent Km values for glucose-6-phosphate and fructose-6-phosphate were 8.7 and 1.0 mM, respectively, and the corresponding apparentV max values were 800 and 130 U/mg. The enzyme had a temperature optimum of 96°C and showed a significant thermostability up to 100°C, which is in accordance with its physiological function under hyperthermophilic conditions. Based on the N-terminal amino acid sequence of the subunit, a single open reading frame (ORF; Pf_209264) was identified in the genome of P. furiosus. The ORF was characterized by functional overexpression in Escherichia coli as a gene, pgi, encoding glucose-6-phosphate isomerase. The recombinant PGI was purified and showed molecular and kinetic properties almost identical to those of the native PGI purified from P. furiosus. The deduced amino acid sequence of P. furiosus PGI did not reveal significant similarity to the conserved PGI superfamily of eubacteria and eucarya. This is the first description of an archaeal PGI, which represents a novel type of PGI.

scholarly journals Purification and Characterization of the Alanine Aminotransferase from the Hyperthermophilic Archaeon Pyrococcus furiosus and Its Role in Alanine Production

2000 ◽  
Vol 182 (9) ◽  
pp. 2559-2566 ◽  
Author(s):  
Donald E. Ward ◽  
Servé W. M. Kengen ◽  
John van der Oost ◽  
Willem M. de Vos
Keyword(s):  
Molecular Mass ◽  
Alanine Aminotransferase ◽  
Pyrococcus Furiosus ◽  
Sodium Dodecyl ◽  
Northern Analysis ◽  
Transcriptional Level ◽  
Significant Activity ◽  
Genome Database ◽  
Hyperthermophilic Archaeon ◽  
Cell Extracts

ABSTRACT Alanine aminotransferase (AlaAT) was purified from cell extracts of the hyperthermophilic archaeon Pyrococcus furiosusby multistep chromatography. The enzyme has an apparent molecular mass of 93.5 kDa, as estimated by gel filtration, and consists of two identical subunits of 46 kDa, as deduced by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the gene sequence. The AlaAT displayed a broader substrate specificity than AlaATs from eukaryal sources and exhibited significant activity with alanine, glutamate, and aspartate with either 2-oxoglutarate or pyruvate as the amino acceptor. Optimal activity was found in the pH range of 6.5 to 7.8 and at a temperature of over 95°C. The N-terminal amino acid sequence of the purified AlaAT was determined and enabled the identification of the gene encoding AlaAT (aat) in theP. furiosus genome database. The gene was expressed inEscherichia coli, and the recombinant enzyme was purified. The pH and temperature dependence, molecular mass, and kinetic parameters of the recombinant were indistinguishable from those of the native enzyme from P. furiosus. Thek cat/Km values for alanine and pyruvate formation were 41 and 33 s−1mM−1, respectively, suggesting that the enzyme is not biased toward either the formation of pyruvate, or alanine. Northern analysis identified a single 1.2-kb transcript for the aatgene. In addition, both the aat and gdh(encoding the glutamate dehydrogenase) transcripts appear to be coregulated at the transcriptional level, because the expression of both genes was induced when the cells were grown on pyruvate. The coordinated control found for the aat and gdhgenes is in good agreement with these enzymes acting in a concerted manner to form an electron sink in P. furiosus.

scholarly journals Characterization of an Aminoacylase from the Hyperthermophilic Archaeon Pyrococcus furiosus

2001 ◽  
Vol 183 (14) ◽  
pp. 4259-4268 ◽  
Author(s):  
Sherry V. Story ◽  
Amy M. Grunden ◽  
Michael W. W. Adams
Keyword(s):  
Amino Acids ◽  
Recombinant Protein ◽  
Pyrococcus Furiosus ◽  
Protein A ◽  
Genome Database ◽  
Hyperthermophilic Archaeon ◽  
Protein Renaturation ◽  
Cell Extracts ◽  
Growth Substrates ◽  
Catalytically Active

ABSTRACT Aminoacylase was identified in cell extracts of the hyperthermophilic archaeon Pyrococcus furiosus by its ability to hydrolyze N-acetyl-l-methionine and was purified by multistep chromatography. The enzyme is a homotetramer (42.06 kDa per subunit) and, as purified, contains 1.0 ± 0.48 g-atoms of zinc per subunit. Treatment of the purified enzyme with EDTA resulted in complete loss of activity. This was restored to 86% of the original value (200 U/mg) by treatment with ZnCl2 (and to 74% by the addition of CoCl2). After reconstitution with ZnCl2, the enzyme contained 2.85 ± 0.48 g-atoms of zinc per subunit. Aminoacylase showed broad substrate specificity and hydrolyzed nonpolarN-acylated l amino acids (Met, Ala, Val, and Leu), as well as N-formyl-l-methionine. The high Km values for these compounds indicate that the enzyme plays a role in the metabolism of protein growth substrates rather than in the degradation of cellular proteins. Maximal aminoacylase activity withN-acetyl-l-methionine as the substrate occurred at pH 6.5 and a temperature of 100°C. The N-terminal amino acid sequence of the purified aminoacylase was used to identify, in theP. furiosus genome database, a gene that encodes 383 amino acids. The gene was cloned and expressed in Escherichia coli by using two approaches. One involved the T7lac promoter system, in which the recombinant protein was expressed as inclusion bodies. The second approach used the Trx fusion system, and this produced soluble but inactive recombinant protein. Renaturation and reconstitution experiments with Zn2+ ions failed to produce catalytically active protein. A survey of databases showed that, in general, organisms that contain a homolog of theP. furiosus aminoacylase (≥50% sequence identity) utilize peptide growth substrates, whereas those that do not contain the enzyme are not known to be proteolytic, suggesting a role for the enzyme in primary catabolism.

The glutamate dehydrogenase-encoding gene of the hyperthermophilic archaeon Pyrococcus furiosus: sequence, transcription and analysis of the deduced amino acid sequence

Gene ◽  
1993 ◽  
Vol 132 (1) ◽  
pp. 143-148 ◽  
Author(s):  
Rik I.L. Eggen ◽  
Ans C.M. Geerling ◽  
Kerstin Waldkötter ◽  
Garabed Antranikian ◽  
Willem M. de Vos
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Glutamate Dehydrogenase ◽  
Pyrococcus Furiosus ◽  
Hyperthermophilic Archaeon ◽  
Encoding Gene

Characterization of a novel moderate-substrate specificity amino acid racemase from the hyperthermophilic archaeon Thermococcus litoralis

2021 ◽  
Author(s):  
Ryushi Kawakami ◽  
Chinatsu Kinoshita ◽  
Tomoki Kawase ◽  
Mikio Sato ◽  
Junji Hayashi ◽  
...  
Keyword(s):  
Amino Acid ◽  
Substrate Specificity ◽  
Enzyme Stability ◽  
Hyperthermophilic Archaea ◽  
Thermococcus Litoralis ◽  
Hyperthermophilic Archaeon ◽  
Aminobutyrate Aminotransferase ◽  
Chaperone Protein ◽  
Amino Acid Racemase

Abstract The amino acid sequence of the OCC_10945 gene product from the hyperthermophilic archaeon Thermococcus litoralis DSM5473, originally annotated as γ-aminobutyrate aminotransferase, is highly similar to that of the uncharacterized pyridoxal 5ʹ-phosphate (PLP)-dependent amino acid racemase from Pyrococcus horikoshii. The OCC_10945 enzyme was successfully overexpressed in Escherichia coli by co-expression with a chaperone protein. The purified enzyme demonstrated PLP-dependent amino acid racemase activity primarily toward Met and Leu. Although PLP contributed to enzyme stability, it only loosely bound to this enzyme. Enzyme activity was strongly inhibited by several metal ions, including Co2+ and Zn2+, and non-substrate amino acids such as l-Arg and l-Lys. These results suggest that the underlying PLP-binding and substrate recognition mechanisms in this enzyme are significantly different from those of the other archaeal and bacterial amino acid racemases. This is the first description of a novel PLP-dependent amino acid racemase with moderate substrate specificity in hyperthermophilic archaea.

scholarly journals Unique Presence of a Manganese Catalase in a Hyperthermophilic Archaeon, Pyrobaculum calidifontis VA1

2002 ◽  
Vol 184 (12) ◽  
pp. 3305-3312 ◽  
Author(s):  
Taku Amo ◽  
Haruyuki Atomi ◽  
Tadayuki Imanaka
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Catalase Activity ◽  
Specific Activity ◽  
Homology Search ◽  
Aerobic Conditions ◽  
Hyperthermophilic Archaeon ◽  
Manganese Catalase ◽  
Catalase Gene ◽  
Pyrobaculum Calidifontis

ABSTRACT We had previously isolated a facultatively anaerobic hyperthermophilic archaeon, Pyrobaculum calidifontis strain VA1. Here, we found that strain VA1, when grown under aerobic conditions, harbors high catalase activity. The catalase was purified 91-fold from crude extracts and displayed a specific activity of 23,500 U/mg at 70°C. The enzyme exhibited a Km value of 170 mM toward H2O2 and a k cat value of 2.9 × 104 s−1·subunit−1 at 25°C. Gel filtration chromatography indicated that the enzyme was a homotetramer with a subunit molecular mass of 33,450 Da. The purified catalase did not display the Soret band, which is an absorption band particular to heme enzymes. In contrast to typical heme catalases, the catalase was not strongly inhibited by sodium azide. Furthermore, with plasma emission spectroscopy, we found that the catalase did not contain iron but instead contained manganese. Our biochemical results indicated that the purified catalase was not a heme catalase but a manganese (nonheme) catalase, the first example in archaea. Intracellular catalase activity decreased when cells were grown anaerobically, while under aerobic conditions, an increase in activity was observed with the removal of thiosulfate from the medium, or addition of manganese. Based on the N-terminal amino acid sequence of the purified protein, we cloned and sequenced the catalase gene (katPc ). The deduced amino acid sequence showed similarity with that of the manganese catalase from a thermophilic bacterium, Thermus sp. YS 8-13. Interestingly, in the complete archaeal genome sequences, no open reading frame has been assigned as a manganese catalase gene. Moreover, a homology search with the sequence of katPc revealed that no orthologue genes were present on the archaeal genomes, including those from the “aerobic” (hyper)thermophilic archaea Aeropyrum pernix, Sulfolobus solfataricus, and Sulfolobus tokodaii. Therefore, Kat Pc can be considered a rare example of a manganese catalase from archaea.

scholarly journals A Mono-2-Ethylhexyl Phthalate Hydrolase from a Gordonia sp. That Is Able To Dissimilate Di-2-Ethylhexyl Phthalate

2006 ◽  
Vol 72 (4) ◽  
pp. 2394-2399 ◽  
Author(s):  
Tuguhiro Nishioka ◽  
Makoto Iwata ◽  
Takuya Imaoka ◽  
Maiko Mutoh ◽  
Yoshihiro Egashira ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Contaminated Soil ◽  
Primary Structure ◽  
Independent Group ◽  
Serine Hydrolases ◽  
Cell Extracts ◽  
Significant Homology ◽  
Serine Esterases ◽  
Ethylhexyl Phthalate

ABSTRACT Gordonia sp. strain P8219, a strain able to decompose di-2-ethylhexyl phthalate, was isolated from machine oil-contaminated soil. Mono-2-ethylhexyl phthalate hydrolase was purified from cell extracts of this strain. This enzyme was a 32,164-Da homodimeric protein, and it effectively hydrolyzed monophthalate esters, such as monoethyl, monobutyl, monohexyl, and mono-2-ethylhexyl phthalate. The Km and V max values for mono-2-ethylhexyl phthalate were 26.9 ± 4.3 μM and 18.1 ± 0.9 μmol/min · mg protein, respectively. The deduced amino acid sequence of the enzyme exhibited less than 30% homology with those of meta-cleavage hydrolases which are serine hydrolases but exhibited no significant homology with the sequences of serine esterases. The pentapeptide motif GXSXG, which is conserved in serine hydrolases, was present in the sequence. The enzymatic properties and features of the primary structure suggested that this enzyme is a novel enzyme belonging to an independent group of serine hydrolases.

scholarly journals Extracellular-matrix degradation at acid pH. Avian osteoclast acid collagenase isolation and characterization

1993 ◽  
Vol 290 (3) ◽  
pp. 873-884 ◽  
Author(s):  
H C Blair ◽  
S L Teitelbaum ◽  
L E Grosso ◽  
D L Lacey ◽  
H L Tan ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Substrate Specificity ◽  
Cathepsin B ◽  
Type I Collagen ◽  
Sequence Similarity ◽  
Bone Matrix ◽  
Collagenolytic Activity ◽  
Type I ◽  
Isolation And Characterization

Osteoclasts degrade bone matrix, which is mainly type I collagen and hydroxyapatite, in an acidic extracellular compartment. Thus we reasoned that osteoclasts must produce an acid collagenase. We purified this enzyme, a 31 kDa protein, from avian osteoclast lysates (in 100 mM acetate/1 mM CHAPS/1 mM dithiothreitol, pH 4.4), fractionated by (NH2)2SO4 precipitation, gelatin-affinity, cation exchange, and gel filtration. Fraction activity was measured using diazotized collagen or 3H-labelled cross-linked collagen (decalcified and trypsin-treated metabolically L-[4,5-3H]proline-labelled bone) as substrates. Iodoacetate, leupeptin, antipain, pepstatin and mercurials inhibited collagenolysis by the isolated proteinase; mercurial derivatives could not be re-activated by dithiothreitol. Collagen degradation was maximal at pH 4.4; purified proteinase reproduced the collagenolytic activity of cell lysates. The N-terminal amino acid sequence from the isolated protein and its CNBr degradation fragments showed sequence similarity to mammalian cathepsin Bs, and near-identity with avian liver cathepsin B. Peptide substrate specificity of the osteoclastic enzyme resembled those of mammalian cathepsin B and its avian liver counterpart, but degradation of low-molecular-mass substrates by the osteoclastic enzyme was slower, reflecting generally lower kcat. values. Further, kcat/Km varied less between arginine-containing substrates than for previously reported cathepsin Bs, indicating different substrate specificity of the osteoclast enzyme. Polyclonal antibody raised to a 25 kDa fragment of the enzyme recognized a single 31 kDa band in SDS/PAGE of osteoclast lysates blotted to poly(vinylidene difluoride), adsorbed collagenolytic activity of osteoclast lysates, and stained avian osteoclasts in tissue sections. Degenerate sense- and antisense-oligonucleotide primers, predicted from segments of primary amino acid sequence, amplified a 486 bp DNA fragment; this was cloned and sequenced. Of 162 amino acids encoded, 77% are identical with those of human cathepsin B; hybridization identified a 2.4 kb RNA in osteoclast lysates. We conclude that the major avian osteoclast collagenolytic enzyme is a cathepsin B, whose activity varies from other enzymes of its class.

scholarly journals Plasmid-Encoded asp Operon Confers a Proton Motive Metabolic Cycle Catalyzed by an Aspartate-Alanine Exchange Reaction

2002 ◽  
Vol 184 (11) ◽  
pp. 2906-2913 ◽  
Author(s):  
Keietsu Abe ◽  
Fumito Ohnishi ◽  
Kyoko Yagi ◽  
Tasuku Nakajima ◽  
Takeshi Higuchi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Sequence Analysis ◽  
Amino Acid Sequence ◽  
Expression Vector ◽  
Alcaligenes Faecalis ◽  
E Coli ◽  
Cell Extracts ◽  
Membrane Spanning ◽  
Metabolic Cycle

ABSTRACT Tetragenococcus halophila D10 catalyzes the decarboxylation of l-aspartate with nearly stoichiometric release of l-alanine and CO2. This trait is encoded on a 25-kb plasmid, pD1. We found in this plasmid a putative asp operon consisting of two genes, which we designated aspD and aspT, encoding an l-aspartate-β-decarboxylase (AspD) and an aspartate-alanine antiporter (AspT), respectively, and determined the nucleotide sequences. The sequence analysis revealed that the genes of the asp operon in pD1 were in the following order: promoter → aspD → aspT. The deduced amino acid sequence of AspD showed similarity to the sequences of two known l-aspartate-β-decarboxylases from Pseudomonas dacunhae and Alcaligenes faecalis. Hydropathy analyses suggested that the aspT gene product encodes a hydrophobic protein with multiple membrane-spanning regions. The operon was subcloned into the Escherichia coli expression vector pTrc99A, and the two genes were cotranscribed in the resulting plasmid, pTrcAsp. Expression of the asp operon in E. coli coincided with appearance of the capacity to catalyze the decarboxylation of aspartate to alanine. Histidine-tagged AspD (AspDHis) was also expressed in E. coli and purified from cell extracts. The purified AspDHis clearly exhibited activity of l-aspartate-β-decarboxylase. Recombinant AspT was solubilized from E. coli membranes and reconstituted in proteoliposomes. The reconstituted AspT catalyzed self-exchange of aspartate and electrogenic heterologous exchange of aspartate with alanine. Thus, the asp operon confers a proton motive metabolic cycle consisting of the electrogenic aspartate-alanine antiporter and the aspartate decarboxylase, which keeps intracellular levels of alanine, the countersubstrate for aspartate, high.

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