scholarly journals Purification, Characterization, and Gene Cloning of Purine Nucleosidase from Ochrobactrum anthropi

2001 ◽  
Vol 67 (4) ◽  
pp. 1783-1787 ◽  
Author(s):  
Jun Ogawa ◽  
Sou Takeda ◽  
Sheng-Xue Xie ◽  
Haruyo Hatanaka ◽  
Toshihiko Ashikari ◽  
...  

ABSTRACT A bacterium, Ochrobactrum anthropi, produced a large amount of a nucleosidase when cultivated with purine nucleosides. The nucleosidase was purified to homogeneity. The enzyme has a molecular weight of about 170,000 and consists of four identical subunits. It specifically catalyzes the irreversibleN-riboside hydrolysis of purine nucleosides, theKm values being 11.8 to 56.3 μM. The optimal activity temperature and pH were 50°C and pH 4.5 to 6.5, respectively. Pyrimidine nucleosides, purine and pyrimidine nucleotides, NAD, NADP, and nicotinamide mononucleotide are not hydrolyzed by the enzyme. The purine nucleoside hydrolyzing activity of the enzyme was inhibited (mixed inhibition) by pyrimidine nucleosides, with Ki and Ki ′ values of 0.455 to 11.2 μM. Metal ion chelators inhibited activity, and the addition of Zn2+ or Co2+ restored activity. A 1.5-kb DNA fragment, which contains the open reading frame encoding the nucleosidase, was cloned, sequenced, and expressed inEscherichia coli. The deduced 363-amino-acid sequence including a 22-residue leader peptide is in agreement with the enzyme molecular mass and the amino acid sequences of NH2-terminal and internal peptides, and the enzyme is homologous to known nucleosidases from protozoan parasites. The amino acid residues forming the catalytic site and involved in binding with metal ions are well conserved in these nucleosidases.

1998 ◽  
Vol 88 (11) ◽  
pp. 1174-1178 ◽  
Author(s):  
Drake C. Stenger

Cloned genomes of the CFH, Worland, and Cal/Logan strains of beet curly top virus (BCTV) served as helper viruses to trans-replicate defective (D) DNAs that are incapable of self-replication due to deletions within the C1 open reading frame encoding the replication initiator (Rep) protein. The Logan Rep protein could trans-replicate a Logan-derived D DNA in a transient replication assay conducted in Nicotiana benthamiana leaf disks. However, the Logan Rep protein was unable to trans-replicate D DNAs derived from the CFH or Worland strains. In contrast, the Rep proteins of the CFH and Worland strains could trans-replicate CFH or Worland D DNAs, but not a Logan D DNA. These results indicate that the cis- and trans-acting replication specificity elements of the CFH and Worland strains are compatible and that the three strains of BCTV may be divided into two groupings based upon replication specificity determinants. A comparison of amino acid sequences of the Rep protein for the three BCTV strains suggests that the trans-acting replication specificity element may reside in one or more of 12 amino acid residues that are identical; in two amino acid residues that are chemically similar among the CFH and Worland Rep proteins, yet are different in the Logan Rep protein; or in both. Properties including replication specificity, nucleotide sequence identity, and symptom expression were used as criteria to propose separate species designations for each of the three BCTV strains. In this proposal, the Cal/ Logan strain retains the name BCTV, CFH and the closely related Iranian isolate are designated beet severe curly top virus, and Worland is designated beet mild curly top virus.


1999 ◽  
Vol 65 (7) ◽  
pp. 3001-3007 ◽  
Author(s):  
Frederic Chavagnat ◽  
Michael G. Casey ◽  
Jacques Meyer

ABSTRACT The general aminopeptidase PepN from Streptococcus thermophilus A was purified to protein homogeneity by hydroxyapatite, anion-exchange, and gel filtration chromatographies. The PepN enzyme was estimated to be a monomer of 95 kDa, with maximal activity on N-Lys–7-amino-4-methylcoumarin at pH 7 and 37°C. It was strongly inhibited by metal chelating agents, suggesting that it is a metallopeptidase. The activity was greatly restored by the bivalent cations Co2+, Zn2+, and Mn2+. Except for proline, glycine, and acidic amino acid residues, PepN has a broad specificity on the N-terminal amino acid of small peptides, but no significant endopeptidase activity has been detected. The N-terminal and short internal amino acid sequences of purified PepN were determined. By using synthetic primers and a battery of PCR techniques, the pepN gene was amplified, subcloned, and further sequenced, revealing an open reading frame of 2,541 nucleotides encoding a protein of 847 amino acids with a molecular weight of 96,252. Amino acid sequence analysis of thepepN gene translation product shows high homology with other PepN enzymes from lactic acid bacteria and exhibits the signature sequence of the zinc metallopeptidase family. The pepN gene was cloned in a T7 promoter-based expression plasmid and the 452-fold overproduced PepN enzyme was purified to homogeneity from the periplasmic extract of the host Escherichia coli strain. The overproduced enzyme showed the same catalytic characteristics as the wild-type enzyme.


1991 ◽  
Vol 277 (2) ◽  
pp. 469-475 ◽  
Author(s):  
R Dumas ◽  
M Lebrun ◽  
R Douce

Acetohydroxy acid reductoisomerase (AHRI), the second enzyme in the parallel isoleucine/valine-biosynthetic pathway, catalyses an unusual two-step reaction in which the substrate, either 2-acetolactate or 2-aceto-2-hydroxybutyrate, is converted via an alkyl migration and an NADPH-dependent reduction to give 2,3-dihydroxy-3-methylbutyrate or 2,3-dihydroxy-3-methylvalerate respectively. We have isolated and characterized a full-length cDNA from a lambda gt11 spinach library encoding the complete acetohydroxy acid reductoisomerase protein precursor. The 2050-nucleotide sequence contains a 1785-nucleotide open reading frame. The derived amino acid sequence indicates that the protein precursor consists of 595 amino acid residues including a presequence peptide of 72 amino acid residues. The N-terminal sequence of the first 16 amino acid residues of the purified AHRI confirms the identity of the cDNA. The derived amino acid sequence from this open reading frame shows 23% identity with the deduced amino acid sequences of the Escherichia coli and Saccharomyces cerevisiae AHRI proteins. There are two blocks of conserved amino acid residues in these three proteins. One of these is a sequence similar to the ‘fingerprint’ region of the NAD(P)H-binding site found in a large number of NAD(P)H-dependent oxidoreductases. The other, a short sequence (Lys-Xaa-Xaa-Xaa-Xaa-Xaa-Xaa-Xaa-Ser-His-Gly-Phe) containing the amino acids lysine and histidine, could well be the catalytic site of the first step of the AHRI reaction. Southern-blot analysis indicated that AHRI is encoded by a single gene per haploid genome of about 7.5 kbp containing at least four introns.


1996 ◽  
Vol 319 (3) ◽  
pp. 829-837 ◽  
Author(s):  
William S HAYS ◽  
Steven A. JENISON ◽  
Takashi YAMADA ◽  
Andrzej PASTUSZYN ◽  
Robert H. GLEW

The cytosolic β-glucosidase (EC 3.2.1.21) present in the livers of mammalian species is distinguished by its broad specificity for sugars and its preference for hydrophobic aglycones. We purified the cytosolic β-glucosidase from guinea pig liver and sequenced 142 amino acid residues contained within 12 trypsin digest fragments. Using degenerate oligonucleotide primers deduced from the peptide sequences, a 622 bp cytosolic β-glucosidase cDNA was amplified by reverse-transcriptase PCR, using total guinea pig liver RNA as template. The ‘rapid amplification of cDNA ends (RACE)’ method [Frohman (1993) Methods Enzymol. 218, 340–356] was used to synthesize the remaining segments of the full-length cDNA. The complete cDNA contained 1671 nucleotides with an open reading frame coding for 469 amino acid residues. The amino acid sequence deduced from the cDNA sequence included the amino acid sequences of all 12 trypsin digest fragments derived from the purified enzyme. Amino acid sequence analysis indicates that the guinea pig liver cytosolic β-glucosidase is a Family 1 β-glycosidase and that it is most closely related to mammalian lactase-phlorizin hydrolase. These results suggest that the cytosolic β-glucosidase and lactase-phlorizin hydrolase diverged from a common evolutionary precursor.


Parasitology ◽  
2016 ◽  
Vol 144 (5) ◽  
pp. 641-649 ◽  
Author(s):  
QINGLI NIU ◽  
ZHIJIE LIU ◽  
JIFEI YANG ◽  
GUIQUAN GUAN ◽  
YUPING PAN ◽  
...  

SUMMARYApical membrane antigen-1 (AMA-1) has been described as a potential vaccine candidate in apicomplexan parasites. Here we characterize theama-1gene. The full-lengthama-1gene ofBabesiasp. BQ1 (Lintan) (BLTAMA-1) is 1785 bp, which contains an open reading frame (ORF) encoding a 65-kDa protein of 594 amino acid residues; by definition, the 5′ UTR precedes the first methionine of the ORF. Phylogenetic analysis based on AMA-1 amino acid sequences clearly separated Piroplasmida from other Apicomplexa parasites. TheBabesiasp. BQ1 (Lintan) AMA-1 sequence is most closely associated with that ofB. ovataandB. bigemina, with high bootstrap value. A recombinant protein encoding a conserved region and containing ectodomains I and II of BLTAMA-1 was constructed. BLTrAMA-1-DI/DII proteins were tested for reactivity with sera from sheep infected byBabesiasp. BQ1 (Lintan). In Western-blot analysis, nativeBabesiasp. BQ1 (Lintan) AMA-1 proteins were recognized by antibodies raised in rabbits against BLTrAMA-1in vitro. The results of this study are discussed in terms of gene characterization, taxonomy and antigenicity.


1988 ◽  
Vol 249 (3) ◽  
pp. 661-668 ◽  
Author(s):  
Y Misumi ◽  
K Tashiro ◽  
M Hattori ◽  
Y Sakaki ◽  
Y Ikehara

Rat liver alkaline phosphatase (ALP) was markedly induced by treatment of rats by bile-duct ligation and colchicine injection. Taking this advantage for enrichment of ALP mRNA, we constructed a lambda gt11 liver cDNA library using polyadenylated RNA prepared from the treated rat liver, and isolated an ALP cDNA clone. The 2165 bp cDNA contained an open reading frame that encodes a 524-amino-acid-residue polypeptide with a predicted molecular mass of 57737 Da. The precursor protein contained a presumed signal peptide of 17 amino acid residues followed by 28 amino acid residues identical with the N-terminal sequence determined from the purified rat liver ALP. It was also confirmed that amino acid sequences of two CNBr-cleavage peptides obtained from liver ALP were contained within the cDNA-encoded protein. Five possible N-linked glycosylation sites were found in the molecule and a highly hydrophobic amino acid sequence at the C-terminus. The deduced polypeptide of rat liver ALP showed 88% homology to that of the human liver-type enzyme in osteosarcoma cells. RNA blot hybridization analysis identified a single species of ALP mRNA with 2.7 kb in both the control and the treated rat livers. An approx. 20-fold increase of the mRNA was detected in the treated liver at 12 h after the onset of stimulation, compared with that in the control liver.


1991 ◽  
Vol 273 (3) ◽  
pp. 659-666 ◽  
Author(s):  
C O Evans ◽  
J F Healey ◽  
Y Greene ◽  
H L Bonkovsky

A cDNA from a chick liver library that encodes for haem oxygenase has been cloned and sequenced. Positive clones were identified with monospecific antibodies to the purified enzyme from chick liver and a cDNA of rat haem oxygenase-1. The length of the cDNA is 1258 bases. An open reading frame of 888 bases was identified by comparison of nucleotide and amino acid sequences with those previously identified for haem oxygenase of mammalian or avian origin. The protein corresponding to this fragment of DNA is composed of 296 amino acid residues and has a molecular mass of 33,509 Da, which is similar to that previously estimated for haem oxygenase purified from chick liver. Unequivocal identification of this clone as that complementary to haem oxygenase was provided by (a) comparison of amino acid compositions and partial sequences with those previously established for the purified enzyme, (b) comparison with nucleotide and amino acid sequences for haem oxygenase from rat and human sources and (c) expression in Escherichia coli with production of high levels of mRNA, protein and haem oxygenase activity after exposure of the transfected bacteria to isopropyl beta-D-thiogalactopyranoside (IPTG). Overall, the similarity of chick haem oxygenase to rat and human haem oxygenase (nucleotides 66% and amino acids 62%) is moderately high. The region between proline-129 and alanine-157 is identical in all three enzymes, including histidine-135, which is proposed to play a key role in binding the substrate haem at the active centre of the enzyme. Northern blots also show that treatment of chicks with CdCl2, a potent inducer of haem oxygenase, results in increases in 1.65-1.70 kb mRNA, which hybridizes selectively to the full-length cDNA or to a synthetic 24-base oligonucleotide with sequence identical to that of a portion of the haem oxygenase cDNA. These results suggest that Cd-dependent induction of haem oxygenase is due to increased transcription of the gene or stabilization of its message.


1994 ◽  
Vol 304 (3) ◽  
pp. 787-792 ◽  
Author(s):  
K T Koivuranta ◽  
E H Hakkola ◽  
J K Hiltunen

2,4-Dienoyl-CoA reductase (EC 1.3.1.34) participates in beta-oxidation of (poly)unsaturated enoyl-CoAs and it appears in mammalian mitochondria as two isoforms with molecular masses of 120 and 60 kDa [Hakkola and Hiltunen (1993) Eur. J. Biochem. 215, 199-204]. The 120 kDa isomer is a homotetrameric enzyme, and here we report cDNA cloning of its subunit from human. cDNA clones were isolated by reverse transcriptase-PCR from a fibrosarcoma cell line and by screening from a human liver lambda gt11 cDNA library. The 1128 bp clone contained an open reading frame of 1008 bp encoding a polypeptide of 335 amino acid residues with a predicted molecular mass of 36066 Da. This polypeptide represents the immature monomer of the 120 kDa enzyme, and it contains a predicted N-terminal mitochondrial targeting signal. The amino acid (nucleotide) sequence of human 2,4-dienoyl-CoA reductase shows 82.7% (81.7%) similarity (identity) to the corresponding sequence from the rat. Northern-blot analysis gave a single mRNA species of 1.2 kb in several human tissues, the amounts present in the tissues tested ranking as follows: heart approximately liver approximately pancreas > kidney >> skeletal muscle approximately lung. Immunoblotting of human and rat liver samples with an antibody to the subunit of the rat 120 kDa isoform indicates that the mature human enzyme is larger than its counterpart in the rat. The comparison of amino acid sequences for rat and human enzymes proposes that the difference in the size is 10 amino acid residues. The results show that the rat and human reductases are similar in many characteristics and that the reductase is expressed in human tissues capable of beta-oxidation of fatty acids.


2020 ◽  
Vol 17 (1) ◽  
pp. 59-77
Author(s):  
Anand Kumar Nelapati ◽  
JagadeeshBabu PonnanEttiyappan

Background:Hyperuricemia and gout are the conditions, which is a response of accumulation of uric acid in the blood and urine. Uric acid is the product of purine metabolic pathway in humans. Uricase is a therapeutic enzyme that can enzymatically reduces the concentration of uric acid in serum and urine into more a soluble allantoin. Uricases are widely available in several sources like bacteria, fungi, yeast, plants and animals.Objective:The present study is aimed at elucidating the structure and physiochemical properties of uricase by insilico analysis.Methods:A total number of sixty amino acid sequences of uricase belongs to different sources were obtained from NCBI and different analysis like Multiple Sequence Alignment (MSA), homology search, phylogenetic relation, motif search, domain architecture and physiochemical properties including pI, EC, Ai, Ii, and were performed.Results:Multiple sequence alignment of all the selected protein sequences has exhibited distinct difference between bacterial, fungal, plant and animal sources based on the position-specific existence of conserved amino acid residues. The maximum homology of all the selected protein sequences is between 51-388. In singular category, homology is between 16-337 for bacterial uricase, 14-339 for fungal uricase, 12-317 for plants uricase, and 37-361 for animals uricase. The phylogenetic tree constructed based on the amino acid sequences disclosed clusters indicating that uricase is from different source. The physiochemical features revealed that the uricase amino acid residues are in between 300- 338 with a molecular weight as 33-39kDa and theoretical pI ranging from 4.95-8.88. The amino acid composition results showed that valine amino acid has a high average frequency of 8.79 percentage compared to different amino acids in all analyzed species.Conclusion:In the area of bioinformatics field, this work might be informative and a stepping-stone to other researchers to get an idea about the physicochemical features, evolutionary history and structural motifs of uricase that can be widely used in biotechnological and pharmaceutical industries. Therefore, the proposed in silico analysis can be considered for protein engineering work, as well as for gout therapy.


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