scholarly journals Purification and characterization of two components of epoxypropane isomerase/carboxylase from Xanthobacter Py2

1996 ◽  
Vol 319 (2) ◽  
pp. 499-506 ◽  
Author(s):  
Chan K. N. CHION CHAN KWO ◽  
David J LEAK

Epoxypropane isomerase from Xanthobacter Py2 has been resolved into at least two components (A and B) by ion-exchange chromatography. Both components were required for the degradation of epoxypropane and were purified further. Component A was apparently homohexameric with a subunit Mr of about 44000, and possessed NAD+-dependent dihydrolipoamide dehydrogenase activity and lipoamide reductase activity. It was sensitive to inhibition by o-phenanthroline and the thiol-specific reagents N-ethylmaleimide (NEM) and p-chloromercuribenzoate. Component B was homodimeric with a subunit Mr of 62170 and contained 2 mol·mol-1 FAD. It had an NADPH-dependent lipoamide reductase activity which was sensitive to NEM and p-chloromercuribenzoate. The N-terminal amino acid sequences and monomer sizes of components A and B correspond to those of ORF1 and ORF3 respectively (ORF = open reading frame) of a recently published sequence of a clone which complements mutants unable to degrade epoxypropane. NADPH was found to replace the need for a low-Mr fraction in epoxypropane degradation assays containing components A and B and NAD+. The predicted amino acid sequence of component A (ORF1) has been analysed and shown to contain a potential ADP binding site near the N-terminus and a putative cofactor binding domain near the C-terminus, with sequence similarity to the biotinyl and lipoyl binding domains of biotin-dependent carboxylases and 2-oxoacid dehydrogenases respectively. A reaction mechanism for epoxypropane degradation, incorporating recent evidence for combined isomerization and carboxylation to acetoacetate, is discussed.

1999 ◽  
Vol 342 (3) ◽  
pp. 721-728 ◽  
Author(s):  
Eiji ARIMITSU ◽  
Shinya AOKI ◽  
Syuhei ISHIKURA ◽  
Kumiko NAKANISHI ◽  
Kazuya MATSUURA ◽  
...  

Cynomolgus and Japanese monkey kidneys, dog and pig livers and rabbit lens contain dimeric dihydrodiol dehydrogenase (EC 1.3.1.20) associated with high carbonyl reductase activity. Here we have isolated cDNA species for the dimeric enzymes by reverse transcriptase-PCR from human intestine in addition to the above five animal tissues. The amino acid sequences deduced from the monkey, pig and dog cDNA species perfectly matched the partial sequences of peptides digested from the respective enzymes of these animal tissues, and active recombinant proteins were expressed in a bacterial system from the monkey and human cDNA species. Northern blot analysis revealed the existence of a single 1.3 kb mRNA species for the enzyme in these animal tissues. The human enzyme shared 94%, 85%, 84% and 82% amino acid identity with the enzymes of the two monkey strains (their sequences were identical), the dog, the pig and the rabbit respectively. The sequences of the primate enzymes consisted of 335 amino acid residues and lacked one amino acid compared with the other animal enzymes. In contrast with previous reports that other types of dihydrodiol dehydrogenase, carbonyl reductases and enzymes with either activity belong to the aldo-keto reductase family or the short-chain dehydrogenase/reductase family, dimeric dihydrodiol dehydrogenase showed no sequence similarity with the members of the two protein families. The dimeric enzyme aligned with low degrees of identity (14-25%) with several prokaryotic proteins, in which 47 residues are strictly or highly conserved. Thus dimeric dihydrodiol dehydrogenase has a primary structure distinct from the previously known mammalian enzymes and is suggested to constitute a novel protein family with the prokaryotic proteins.


1996 ◽  
Vol 317 (1) ◽  
pp. 285-290 ◽  
Author(s):  
Kenneth A. CORNELL ◽  
R. W. WINTER ◽  
Paula A. TOWER ◽  
Michael K. RISCOE

Two enzymes in the methionine salvage pathway, 5-methylthioribose kinase (MTR kinase) and 5´-methylthioadenosine/S-adenosylhomocysteine nucleosidase (MTA/SAH nucleosidase) were purified from Klebsiellapneumoniae. Chromatography using a novel 5´-(p-aminophenyl)thioadenosine/5-(p-aminophenyl)thioribose affinity matrix allowed the binding and selective elution of each of the enzymes in pure form. The molecular mass, substrate kinetics and N-terminal amino acid sequences were characterized for each of the enzymes. Purified MTR kinase exhibits an apparent molecular mass of 46–50 kDa by SDS/PAGE and S200HR chromatography, and has a Km for MTR of 12.2 μM. Homogeneous MTA/SAH nucleosidase displays a molecular mass of 26.5 kDa by SDS/PAGE, and a Km for MTA of 8.7 μM. Comparisons of the N-terminal sequences obtained for each of the enzymes with protein-sequence databases failed to reveal any significant sequence similarities to known proteins. However, the amino acid sequence obtained for the nucleosidase did share a high degree of sequence similarity with the putative translation product of an open reading frame in Escherichia coli, thus providing a tentative identification of this gene as encoding an MTA/SAH nucleosidase.


1989 ◽  
Vol 9 (9) ◽  
pp. 4038-4045
Author(s):  
E Stavnezer ◽  
D Brodeur ◽  
L A Brennan

The nucleotide sequence of a biologically active v-ski gene from a cloned proviral segment shows that ski is a 1,312-base sequence embedded in the p19 region of the avian leukosis virus gag gene. The v-ski sequence contains a single open translational reading frame that encodes a polypeptide with a molecular mass of 49,000 daltons. The predicted amino acid sequence includes nuclear localization motifs that have been identified in other nuclear oncoproteins. It also contains a proline-rich region and a set of cysteine and histidine residues that could constitute a metal-binding domain. Two regions of the amino acid sequences of v-ski and v-myc are related, and the two proteins exhibit similar distributions of hydrophobic and hydrophilic amino acids. Cloned segments of the chicken c-ski proto-oncogene totaling 65 kilobases have been analyzed, and regions related to v-ski have been sequenced. The results indicate that v-ski is derived from at least five coding exons of c-ski, that it is correctly spliced, and that it is missing c-ski coding sequences at both its 5' and 3' ends. The c-ski and avian leukosis virus sequences that overlap the 5' virus/v-ski junction in Sloan-Kettering virus contain an 18-of-20-base sequence match that presumably played a role in the transduction of ski by facilitating virus/c-ski recombination.


1995 ◽  
Vol 108 (7) ◽  
pp. 2683-2692
Author(s):  
J. Marshall ◽  
D.V. Holberton

Previously described extended proteins from the cytoskeleton of Giardia lamblia (beta-giardin, median body protein) have been found to be segmented coiled coils with regular structural repeat patterns in their amino acid sequences. Screening a lambda ZAPII library derived from Giardia genomic DNA with an antibody directed against a 34 × 10(3) M(r) giardin isoform selected a gene encoding a much larger polypeptide chain (HPSR2), the sequence of which was determined by chromosome walking the open reading frame. The complete gene has been cloned and expressed as a recombinant protein of 183 × 10(3) M(r). The predicted amino acid sequence of the protein has identifiable features suggesting that it might be a motor protein with an amino-terminal hydrolytic domain attached to a long coiled coil stalk. The presumed head domain is 211 residues and contains a P-loop sequence conserved in purine nucleotide-binding proteins. The remaining 1409 amino acids mainly make up a region of heptad repeats such as in myosin or the kinesin stalk, ending in a small (67 amino acids) carboxy-terminal domain. Fourier analysis of the predicted stalk shows the presence of a strong physical repeat created by regular heptad phase changes dividing the coil into segments of 25 residues. This structure most closely resembles the smaller microtubule-associated median body protein which has segments of 24 residues.


1990 ◽  
Vol 45 (9-10) ◽  
pp. 987-998 ◽  
Author(s):  
Michael D. Partis ◽  
Rudolf Grimm

Abstract The amino acid sequences of phytochrome from Avena sativa, Oryza sativa, Curcurbita pepo, Pisum sativum and Arabidopsis thaliana have been analyzed with a variety of computer programs, with a view to identifying areas of the protein which contribute to the properties of this photoreceptor. A region at the C-terminus has been shown to be amphiphilic, and by ana­logy with surface-seeking peptides, may be responsible for interaction of phytochrome with lipid bilayers. Possible targeting sequences in phytochromes have been identified, including a series of four basic residues which correspond to those responsible for transport of nuclear-located proteins. Sites capable of post-translational modification have been found in monocot sequences, but not in dicot sequences. Areas of the phytochrome molecule which are exposed on the surface of the portein, and which are therefore capable of interaction with other cellular macromolecules, have been identified. Analogies with other biliproteins have been used to define minimum chromophore-protein interactions. Possible enzymic activities associated with phytochromes have been discussed with respect to local amino acid sequence similarity with enzymes.


1999 ◽  
Vol 181 (19) ◽  
pp. 6003-6009 ◽  
Author(s):  
Jimmy S. H. Tsang ◽  
Laiju Sam

ABSTRACT Burkholderia cepacia MBA4 has been shown to produce a single dehalogenase batch culture. Moreover, other cryptic dehalogenases were also detected when the cells were grown in continuous culture. In this paper, we report the cloning and characterization of one of the cryptic dehalogenases in MBA4. This cryptic haloacid dehalogenase, designated Chd1, was expressed constitutively in Escherichia coli. This recombinant Chd1 had a relative molecular weight of 58,000 and existed predominantly as a dimer. The subunits had a relative molecular weight of 27,000. Chd1 exhibited isomer specificity, being active towards thel-isomer of 2-monochloropropionic acid only. The structural gene, chd1, was isolated on a 1.7-kb PstI fragment. This fragment contains a functional promoter, because expression of chd1 in E. coli is orientation independent. The nucleotide sequence of this fragment was determined and characterized. An open reading frame of 840 bp encoding a putative peptide of 280 amino acids was identified. This corresponds closely with the size of the subunit. The nucleotide sequence of chd1 did not show any homology with those of other dehalogenase genes. Comparison of the predicted amino acid sequence, however, shows significant homology, ranging from 42 to 50%, with the amino acid sequences of many other dehalogenases. Chd1 is unusual in having a long leader sequence, a property of periplasmic enzymes.


1989 ◽  
Vol 9 (9) ◽  
pp. 4038-4045 ◽  
Author(s):  
E Stavnezer ◽  
D Brodeur ◽  
L A Brennan

The nucleotide sequence of a biologically active v-ski gene from a cloned proviral segment shows that ski is a 1,312-base sequence embedded in the p19 region of the avian leukosis virus gag gene. The v-ski sequence contains a single open translational reading frame that encodes a polypeptide with a molecular mass of 49,000 daltons. The predicted amino acid sequence includes nuclear localization motifs that have been identified in other nuclear oncoproteins. It also contains a proline-rich region and a set of cysteine and histidine residues that could constitute a metal-binding domain. Two regions of the amino acid sequences of v-ski and v-myc are related, and the two proteins exhibit similar distributions of hydrophobic and hydrophilic amino acids. Cloned segments of the chicken c-ski proto-oncogene totaling 65 kilobases have been analyzed, and regions related to v-ski have been sequenced. The results indicate that v-ski is derived from at least five coding exons of c-ski, that it is correctly spliced, and that it is missing c-ski coding sequences at both its 5' and 3' ends. The c-ski and avian leukosis virus sequences that overlap the 5' virus/v-ski junction in Sloan-Kettering virus contain an 18-of-20-base sequence match that presumably played a role in the transduction of ski by facilitating virus/c-ski recombination.


1979 ◽  
Author(s):  
Takashi Morita ◽  
Craig Jackson

Bovine Factor X is eluted in two forms (X1and X2) from anion exchange chromatographic columns. These two forms have indistinguishable amino acid compositions, molecular weights and specific activities. The amino acid sequences containing the γ-carboxyglutamic acid residues have been shown to be identical in X1 and X2(H. Morris, personal communication). An activation peptide is released from the N-terminal region of the heavy chain of Factor X by an activator from Russell’s viper venom. This peptide can be isolated after activation by gel filtration on Sephadex G-100 under nondenaturing conditions. The activation peptides from a mixture of Factors X1 and X2 were separated into two forms by anion-exchange chromatography. The activation peptide (AP1) which eluted first was shown to be derived from Factor X1. while the activation peptiae (AP2) which eluted second was shown to be derived from X2 on the basis of chromatographic separations carried out on Factors X1 and X2 separately. Factor Xa was eluted as a symmetrical single peak. On the basis of these and other data characterizing these products, we conclude that the difference between X1 and X2 are properties of the structures of the activation peptides. (Supported by a grant HL 12820 from the National Heart, Lung and Blood Institute. C.M.J. is an Established Investigator of the American Heart Association).


2021 ◽  
Author(s):  
Liying Sun ◽  
Ziqian Lian ◽  
Subha Das ◽  
Jingxian Luo ◽  
Ida Bagus Andika

Abstract In this study, we describe the full-length genome sequence of a novel ourmia-like mycovirus, tentatively designated Botryosphaeria dothidea ourmia-like virus 1 (BdOLV1), isolated from the phytopathogenic fungus, Botryosphaeria dothidea strain P8, associated with apple ring rot in Shanxi province, China. The complete BdOLV1 genome is comprised of 2797 nucleotides, a positive-sense (+) single-stranded RNA (ssRNA) with a single open reading frame (ORF). The ORF putatively encodes a 642-amino acid polypeptide with conserved RNA-dependent RNA polymerase (RdRp) motifs, related to viruses of the family Botourmiaviridae. Phylogenetic analysis based on the RdRp amino acid sequences showed that BdOLV1 is grouped with oomycete-infecting unclassified viruses closely related to the genus Botoulivirus in Botourmiaviridae. This is the first report of a novel (+)ssRNA virus in B. dothidea related to the genus Botoulivirus in the family Botourmiaviridae.


1986 ◽  
Vol 6 (5) ◽  
pp. 1711-1721
Author(s):  
E M McIntosh ◽  
R H Haynes

The dCMP deaminase gene (DCD1) of Saccharomyces cerevisiae has been isolated by screening a Sau3A clone bank for complementation of the dUMP auxotrophy exhibited by dcd1 dmp1 haploids. Plasmid pDC3, containing a 7-kilobase (kb) Sau3A insert, restores dCMP deaminase activity to dcd1 mutants and leads to an average 17.5-fold overproduction of the enzyme in wild-type cells. The complementing activity of the plasmid was localized to a 4.2-kb PvuII restriction fragment within the Sau3A insert. Subcloning experiments demonstrated that a single HindIII restriction site within this fragment lies within the DCD1 gene. Subsequent DNA sequence analysis revealed a 936-nucleotide open reading frame encompassing this HindIII site. Disruption of the open reading frame by integrative transformation led to a loss of enzyme activity and confirmed that this region constitutes the dCMP deaminase gene. Northern analysis indicated that the DCD1 mRNA is a 1.15-kb poly(A)+ transcript. The 5' end of the transcript was mapped by primer extension and appears to exhibit heterogeneous termini. Comparison of the amino acid sequence of the T2 bacteriophage dCMP deaminase with that deduced for the yeast enzyme revealed a limited degree of homology which extends over the entire length of the phage polypeptide (188 amino acids) but is confined to the carboxy-terminal half of the yeast protein (312 amino acids). A potential dTTP-binding site in the yeast and phage enzymes was identified by comparison of homologous regions with the amino acid sequences of a variety of other dTTP-binding enzymes. Despite the role of dCMP deaminase in dTTP biosynthesis, Northern analysis revealed that the DCD1 gene is not subject to the same cell cycle-dependent pattern of transcription recently found for the yeast thymidylate synthetase gene (TMP1).


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