1
|
Chahine MN, Pierce GN. Therapeutic Targeting of Nuclear Protein Import in Pathological Cell Conditions. Pharmacol Rev 2009; 61:358-72. [DOI: 10.1124/pr.108.000620] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
2
|
Abstract
Information theory was used to build a promoter model that accounts for the -10, the -35 and the uncertainty of the gap between them on a common scale. Helical face assignment indicated that base -7, rather than -11, of the -10 may be flipping to initiate transcription. We found that the sequence conservation of sigma70 binding sites is 6.5 +/- 0.1 bits. Some promoters lack a -35 region, but have a 6.7 +/- 0.2 bit extended -10, almost the same information as the bipartite promoter. These results and similarities between the contacts in the extended -10 binding and the -35 suggest that the flexible bipartite sigma factor evolved from a simpler polymerase. Binding predicted by the bipartite model is enriched around 35 bases upstream of the translational start. This distance is the smallest 5' mRNA leader necessary for ribosome binding, suggesting that selective pressure minimizes transcript length. The promoter model was combined with models of the transcription factors Fur and Lrp to locate new promoters, to quantify promoter strengths, and to predict activation and repression. Finally, the DNA-bending proteins Fis, H-NS and IHF frequently have sites within one DNA persistence length from the -35, so bending allows distal activators to reach the polymerase.
Collapse
Affiliation(s)
| | | | | | - Thomas D. Schneider
- To whom correspondence should be addressed. Tel: +1 301 846 5581; Fax: +1 301 846 5598;
| |
Collapse
|
3
|
Pedersen AG, Jensen LJ, Brunak S, Staerfeldt HH, Ussery DW. A DNA structural atlas for Escherichia coli. J Mol Biol 2000; 299:907-30. [PMID: 10843847 DOI: 10.1006/jmbi.2000.3787] [Citation(s) in RCA: 178] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have performed a computational analysis of DNA structural features in 18 fully sequenced prokaryotic genomes using models for DNA curvature, DNA flexibility, and DNA stability. The structural values that are computed for the Escherichia coli chromosome are significantly different from (and generally more extreme than) that expected from the nucleotide composition. To aid this analysis, we have constructed tools that plot structural measures for all positions in a long DNA sequence (e.g. an entire chromosome) in the form of color-coded wheels (http://www.cbs.dtu. dk/services/GenomeAtlas/). We find that these "structural atlases" are useful for the discovery of interesting features that may then be investigated in more depth using statistical methods. From investigation of the E. coli structural atlas, we discovered a genome-wide trend, where an extended region encompassing the terminus displays a high of level curvature, a low level of flexibility, and a low degree of helix stability. The same situation is found in the distantly related Gram-positive bacterium Bacillus subtilis, suggesting that the phenomenon is biologically relevant. Based on a search for long DNA segments where all the independent structural measures agree, we have found a set of 20 regions with identical and very extreme structural properties. Due to their strong inherent curvature, we suggest that these may function as topological domain boundaries by efficiently organizing plectonemically supercoiled DNA. Interestingly, we find that in practically all the investigated eubacterial and archaeal genomes, there is a trend for promoter DNA being more curved, less flexible, and less stable than DNA in coding regions and in intergenic DNA without promoters. This trend is present regardless of the absolute levels of the structural parameters, and we suggest that this may be related to the requirement for helix unwinding during initiation of transcription, or perhaps to the previously observed location of promoters at the apex of plectonemically supercoiled DNA. We have also analyzed the structural similarities between groups of genes by clustering all RNA and protein-encoding genes in E. coli, based on the average structural parameters. We find that most ribosomal genes (protein-encoding as well as rRNA genes) cluster together, and we suggest that DNA structure may play a role in the transcription of these highly expressed genes.
Collapse
MESH Headings
- Bacterial Proteins/genetics
- Base Pairing/genetics
- Color
- Computational Biology
- Computer Simulation
- Crystallography, X-Ray
- DNA, Bacterial/chemistry
- DNA, Bacterial/genetics
- DNA, Superhelical/chemistry
- DNA, Superhelical/genetics
- Deoxyribonuclease I/metabolism
- Escherichia coli/genetics
- Genes, Bacterial/genetics
- Genome, Bacterial
- Models, Molecular
- Nucleic Acid Conformation
- Nucleosomes/chemistry
- Nucleosomes/genetics
- Pattern Recognition, Automated
- Phylogeny
- Pliability
- Promoter Regions, Genetic/genetics
- RNA, Bacterial/genetics
- Software
- Statistics as Topic
- Thermodynamics
Collapse
Affiliation(s)
- A G Pedersen
- Center for Biological Sequence Analysis, Department of Biotechnology, The Technical University of Denmark, Building 208, DK-2800 Lyngby, Denmark
| | | | | | | | | |
Collapse
|
4
|
Sanz R, Marı N I, Ruiz-Santa-Quiteria JA, Orden JA, Cid D, Diez RM, Silhadi KS, Amils R, de la Fuente R. Catalase deficiency in Staphylococcus aureus subsp. anaerobius is associated with natural loss-of-function mutations within the structural gene. MICROBIOLOGY (READING, ENGLAND) 2000; 146 ( Pt 2):465-475. [PMID: 10708385 DOI: 10.1099/00221287-146-2-465] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Degenerate oligonucleotide primers based on internal peptide sequences obtained by HPLC from purified Staphylococcus aureus catalase were used to locate the S. aureus and S. aureus subsp. anaerobius kat regions by PCR. Southern hybridization analysis with a probe derived from a 1.1 kb PCR-amplified fragment showed that a single copy of the putative catalase gene was present in the S. aureus and S. aureus subsp. anaerobius chromosome. The nucleotide sequence of S. aureus katA revealed a 1518 bp open reading frame for a protein with 505 amino acids and a predicted molecular mass of 58347 Da, whereas S. aureus subsp. anaerobius katB is 1368 nt long and encodes a polypeptide of 455 amino acids with a predicted molecular mass of 52 584 Da. These catalases are highly homologous to typical monofunctional catalases from prokaryotes. The active-site residues, proximal and distal haem-binding ligands and NADPH-binding residues of the bovine liver catalase-type enzyme were highly conserved in S. aureus KatA. Escherichia coli cells carrying cloned katA had a catalase activity approximately 1000 times that of untransformed E. coli, but no detectable increase in catalase activity was observed with E. coli carrying cloned katB. Northern blotting showed the presence of a kat-specific transcript in S. aureus subsp. anaerobius, suggesting that the lack of catalase activity in this bacterium is due to a post-transcriptional alteration. Compared to the nucleotide sequence of katA, katB showed a single base-pair deletion and six mis-sense mutations, and these alterations were present in three other S. aureus subsp. anaerobius strains analysed. The deletion, located at 1338 bp from the initiation codon, originates a shift of the nucleotide reading frame and is responsible for the premature translation termination at 1368 bp, generating a KatB polypeptide 50 amino acid residues shorter than KatA. Moreover, four of the mis-sense mutations present in katB lead to non-conservative amino acid replacements, the most significant being that located at residue 317 (Pro in KatA-->Ser in KatB) because the affected amino acid is involved in determining the proximal haem-binding site. Both the main alterations found in KatB (the deletion and the substitution in residue 317) seem to contribute to the lack of catalase activity in S. aureus subsp. anaerobius, as deduced from results obtained with chimeric catalase constructs.
Collapse
Affiliation(s)
- Rosario Sanz
- Departamento Patologı́a Animal I, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid, Spain1
| | - Irma Marı N
- Centro de Biologı́a Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain2
| | - Jose A Ruiz-Santa-Quiteria
- Departamento Patologı́a Animal I, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid, Spain1
| | - Jose A Orden
- Departamento Patologı́a Animal I, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid, Spain1
| | - Dolores Cid
- Departamento Patologı́a Animal I, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid, Spain1
| | - Rosa M Diez
- Departamento Patologı́a Animal I, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid, Spain1
| | - K Souad Silhadi
- Centre National de Référence de Toxémies à Staphylocoques, EA 1655, Faculté de Médecine, rue Guillaume Paradin, 69372 Lyon cedex 08, France3
| | - Ricardo Amils
- Centro de Biologı́a Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain2
| | - Ricardo de la Fuente
- Departamento Patologı́a Animal I, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid, Spain1
| |
Collapse
|
5
|
|
6
|
Lisser S, Margalit H. Determination of common structural features in Escherichia coli promoters by computer analysis. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 223:823-30. [PMID: 8055959 DOI: 10.1111/j.1432-1033.1994.tb19058.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Escherichia coli promoters show a large degree of sequence variation. However, they are all recognized specifically by RNA polymerase as the sites for transcription initiation, suggesting that they share common basic structural features distinguishing them from the rest of the sequence. Our hypothesis is that the promoter is determined not only by the two consensus sequences at -10 and -35, but also by the surrounding nucleotides, and that it is not only the identity of the nucleotides that is important for promoter function but the presence of specific physical-chemical and structural characteristics that are sequence dependent. This approach is supported by accumulating evidence indicating the role that the DNA conformation may play in modulating protein-DNA interaction. In this study, four intrinsic sequence-dependent characteristics are examined in E. coli promoter regions: helix stability, helix flexibility, and two conformational parameters represented by the DNA tendencies for B-->Z and B-->A transition. The promoter is defined by the consensus sequences and their vicinity and the examined properties are compared between promoter and random sequences. It is demonstrated that both the consensus and flanking regions are less stable, more flexible and show a higher tendency for the B conformation in comparison to random sequences. Discriminant analysis is used to evaluate the relative contributions of the various characteristics.
Collapse
Affiliation(s)
- S Lisser
- Department of Molecular Genetics, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | | |
Collapse
|
7
|
Jyothirmai G, Mishra RK. Differential influence of DNA supercoiling on in vivo strength of promoters varying in structure and organisation in E. coli. FEBS Lett 1994; 340:189-92. [PMID: 8131843 DOI: 10.1016/0014-5793(94)80135-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
DNA supercoiling is known to influence promoter activity in vitro and in vivo in a promoter-dependent manner in prokaryotes. In order to investigate how topology may influence promoter function, we have studied two kinds of promoter variants, (i) where only the spacer region is altered, and (ii) where the same promoter is tandemly repeated in either the same or opposite orientation. These promoters respond very differently to alterations in DNA supercoiling, suggesting that the overall structure of the promoter and its context contribute to the differential response to alterations in supercoiling in vivo.
Collapse
Affiliation(s)
- G Jyothirmai
- Centre for Cellular and Molecular Biology, Hyderabad, India
| | | |
Collapse
|
8
|
Spiegelhalder C, Gerstenecker B, Kersten A, Schiltz E, Kist M. Purification of Helicobacter pylori superoxide dismutase and cloning and sequencing of the gene. Infect Immun 1993; 61:5315-25. [PMID: 8225605 PMCID: PMC281317 DOI: 10.1128/iai.61.12.5315-5325.1993] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The superoxide dismutase (SOD) of Helicobacter pylori, a pathogenic bacterium which colonizes the gastric mucosa, evoking a marked inflammatory response, was purified and characterized, and the N-terminal amino acid sequence was determined. The enzyme consists of two identical subunits each with an apparent molecular weight of 24,000. Analysis of the primary structure and inhibition studies revealed that H. pylori possesses a typical procaryotic iron-containing enzyme. No other isoenzymes could be detected. Indirect gold immunostaining of H. pylori SOD with a polyclonal antibody directed against the iron-containing SOD of Escherichia coli showed a surface-associated localization of the enzyme. The H. pylori SOD gene was cloned by functional complementation of a SOD-deficient E. coli mutant. Sequencing and alignment revealed striking homology to the following facultative intracellular human pathogens: Listeria ivanovii, Listeria monocytogenes, Coxiella burnetti, Porphyromonas gingivalis, Legionella pneumophila, and Entamoeba histolytica. An open reading frame of 642 bp encoding 214 amino acids was determined. There was no leader sequence detectable. Cloning of the H. pylori SOD gene is one of the prerequisites to investigation of its pathophysiological role in the defense against antimicrobial mechanisms of polymorphonuclear granulocytes.
Collapse
Affiliation(s)
- C Spiegelhalder
- Institute for Medical Microbiology and Hygiene, Freiburg, Germany
| | | | | | | | | |
Collapse
|
9
|
Friehs K, Reardon KF. Parameters influencing the productivity of recombinant E. coli cultivations. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 1993; 48:53-77. [PMID: 8460577 DOI: 10.1007/bfb0007196] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In the past 10 to 15 years, many of the promises of microbial genetic engineering have been realized: the use of recombinant Escherichia coli has moved from the laboratory to the production facility, and the manufacture of therapeutic recombinant proteins such as human growth hormone and interleukins is a rapidly growing industry. Along with this progress, however, have come new problems to solve: bioreactor operators have discovered that large-scale cultivations of plasmid-containing bacteria do not behave in exactly the same way as those of plasmid-free cells, plasmid stability has been recognized as a major hurdle, and the protein product might not be present in a soluble form but rather as intracellular granules that resist solubilization. These and other difficulties represent a new generation of challenges for genetic engineering. However, genetic engineering can do more than solve these problems. Molecular biological techniques also have the ability to create new opportunities: to produce new compounds, to use cheaper substrates, to facilitate downstream processing, and to optimize production in new ways. The productivity of a cultivation can generally be expressed as the product of the cell density and the specific biological activity. Both of these parameters are influenced by a variety of factors. For recombinant cultivations, though, the level of biological activity, a reflection of the plasmid copy number and expression efficiency, is the more interesting and important consideration and will therefore be given more attention in our review. In this contribution, our general goal is to discuss the factors that influence the productivity of recombinant E. coli cultivations, covering parameters relating to DNA; parameters relating to protein synthesis; parameters relating to proteins; and parameters relating to downstream processing. The object is not to tell the reader how to choose the perfect plasmid, host, and cultivation conditions, but to make known the many variables involved in designing a recombinant process and to point out recent and potential advances made possible by genetic engineering. The discussion focuses on the production of a protein, but many of the same concepts apply to other cultivations of recombinant E. coli, including cases in which the desired product is not a protein or the cells have been designed for a special metabolic capability such as pollutant biodegradation.
Collapse
Affiliation(s)
- K Friehs
- Technische Fakultät, AG Fermentationstechnik, Universität Bielefeld, Germany
| | | |
Collapse
|
10
|
Abstract
The 5' ends of the Tn10-encoded mRNAs have been analyzed by quantitative primer extensions of the in vivo synthesized RNA and in vitro run-off transcription. The gene is transcribed by a tandem promoter system consisting of PR1 and PR2. While PR1 contributes about 25% of the total PR activity in vitro, more than 95% of the in vivo-produced transcripts originate from PR2. Transcription from PR2 shows extensive heterogeneity at the 5' ends of the mRNAs in vitro and most likely also in vivo. A deletional and oligodeoxyribonucleotide-directed mutational analysis of the PR2 transcript reveals that length heterogeneity results from reiterative copying of a run of five A's at the transcription start point. In vivo transcription leads to longer reiteration products than in vitro transcription.
Collapse
Affiliation(s)
- U Gülland
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander Universität Erlangen-Nürnberg, Germany
| | | |
Collapse
|
11
|
Gulig PA, Caldwell AL, Chiodo VA. Identification, genetic analysis and DNA sequence of a 7.8-kb virulence region of the Salmonella typhimurium virulence plasmid. Mol Microbiol 1992; 6:1395-411. [PMID: 1322485 DOI: 10.1111/j.1365-2958.1992.tb00860.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The 90-kilobase (kb) virulence plasmid of Salmonella typhimurium is responsible for invasion from the intestines to mesenteric lymph nodes and spleens of orally inoculated mice. We used Tn5 and aminoglycoside phosphotransferase (aph) gene insertion mutagenesis and deletion mutagenesis of a previously identified 14-kb virulence region to reduce this virulence region to 7.8kb. The 7.8-kb virulence region subcloned into a low copy-number vector conferred a wild-type level of splenic infection to virulence plasmid-cured S. typhimurium and conferred essentially a wild-type oral LD50. Insertion mutagenesis identified five loci essential for virulence, and DNA sequence analysis of the virulence region identified six open reading frames. Expected protein products were identified from four of the six genes, with three of the proteins identified as doublet bands in Escherichia coli minicells. Three of the five mutated genes were able to be complemented by clones containing only the corresponding wild-type gene. Only one of the five deduced amino acid sequences, that of the positive regulatory element, SpvR, possessed significant homology to other proteins. The codon usage for the virulence genes showed no codon bias, which is consistent with the low levels of expression observed for the corresponding proteins. Consensus promoters for several different sigma factors were identified upstream of several of the genes, whereas only consensus Rho-dependent termination sequences were observed between certain of the genes. The operon structure of this virulence region therefore appears to be complex. The construction of the cloned 7.8-kb virulence region and the determination of the DNA sequence will aid in the further genetic analysis of the five plasmid-encoded virulence genes of S. typhimurium.
Collapse
Affiliation(s)
- P A Gulig
- Department of Immunology and Medical Microbiology, University of Florida College of Medicine, Gainesville 32610-0266
| | | | | |
Collapse
|
12
|
Lee JK, Kaplan S. cis-acting regulatory elements involved in oxygen and light control of puc operon transcription in Rhodobacter sphaeroides. J Bacteriol 1992; 174:1146-57. [PMID: 1735709 PMCID: PMC206407 DOI: 10.1128/jb.174.4.1146-1157.1992] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Transcriptional expression of the puc operon in Rhodobacter sphaeroides is highly regulated by both oxygen and light. The approximately 600 bp of DNA upstream of the 5' ends of the two puc-specific transcripts encompasses two functionally separable cis-acting domains. The upstream regulatory region (URS) (-629 to -150) is responsible for enhanced transcriptional regulation of puc operon expression by oxygen and light. The more proximal upstream region (downstream regulatory region [DRS]), containing putative promoter(s), operator(s), and factor binding sites (-150 to -1), is involved in unenhanced transcriptional expression of the puc operon under aerobic and anaerobic conditions. Thus, the DRS shows normal derepression of puc operon expression when cells are shifted from aerobic to photosynthetic growth conditions in terms of percent change but does not show the potential range of expression that is only observed when elements of the URS are present. Because of these observations, we have made a distinction between anaerobic control (describing the shift) and oxygen control (describing the magnitude of derepression). Promoter(s) and/or activator function(s) of the puc operon is associated with a 35-bp DNA region between -92 and -57. Homologous sequences at -10 to -27 and -35 to -52 appear to involve additional regulatory elements: mutations at -12 (A to C) and -26 (G to A) result in partial derepression of puc operon expression under conditions of high aeration. Both point mutations require the upstream regulatory region (-629 to -150) to be present in cis for partial derepression of puc operon transcription under aerobic conditions. Immediately upstream of the promoter and/or activator region are overlapping consensus sequences for IHF (integratin host factor) and FNR (fumarate nitrate reductase) (-105 to -129). This region appears to be essential for enhanced expression of the puc operon. Thus, these two regulatory domains (URS and DRS) appear to involve approximately seven unique regulatory elements. In addition, the data reveal a direct interaction between the URS (-629 to -150) and the DRS (-150 to -1).
Collapse
Affiliation(s)
- J K Lee
- Department of Microbiology and Molecular Genetics, University of Texas Medical School, P.O. Box 20708, Houston 77225
| | | |
Collapse
|
13
|
Haas A, Goebel W. Cloning of a superoxide dismutase gene from Listeria ivanovii by functional complementation in Escherichia coli and characterization of the gene product. MOLECULAR & GENERAL GENETICS : MGG 1992; 231:313-22. [PMID: 1736100 DOI: 10.1007/bf00279805] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A gene encoding superoxide dismutase (EC 1.15.1.1., SOD) was isolated from a plasmid library of chromosomal DNA from Listeria ivanovii by functional complementation of an SOD-negative Escherichia coli host. The nucleotide sequence of the cloned gene was determined and contained an open reading frame which codes for a protein of 202 amino acid residues (calculated molecular weight 22755 Da including the amino-terminal methionine residue). Comparison of the deduced amino acid sequence of L. ivanovii SOD with previously reported SOD amino acid sequences revealed considerable homologies with Fe- and Mn-dependent SODs. Enzymatic analyses using cell lysates and the purified recombinant enzyme indicated that this SOD is manganese-dependent. The recombinant SOD accounted for up to 30% of the total soluble protein in recombinant E. coli and protected sodA sodB mutants against the toxic effects of paraquat. Subunits of the recombinant Listeria SOD and of both E. coli SODs formed enzymatically active hybrids in vivo.
Collapse
Affiliation(s)
- A Haas
- Institut für Genetik und Mikrobiologie, Universität Würzburg, FRG
| | | |
Collapse
|
14
|
Haas A, Brehm K, Kreft J, Goebel W. Cloning, characterization, and expression in Escherichia coli of a gene encoding Listeria seeligeri catalase, a bacterial enzyme highly homologous to mammalian catalases. J Bacteriol 1991; 173:5159-67. [PMID: 1860824 PMCID: PMC208208 DOI: 10.1128/jb.173.16.5159-5167.1991] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A gene coding for catalase (hydrogen-peroxide:hydrogen-peroxide oxidoreductase; EC 1.11.1.6) of the gram-positive bacterium Listeria seeligeri was cloned from a plasmid library of EcoRI-digested chromosomal DNA, with Escherichia coli DH5 alpha as a host. The recombinant catalase was expressed in E. coli to an enzymatic activity approximately 50 times that of the combined E. coli catalases. The nucleotide sequence was determined, and the deduced amino acid sequence revealed 43.2% amino acid sequence identity between bovine liver catalase and L. seeligeri catalase. Most of the amino acid residues which are involved in catalytic activity, the formation of the active center accession channel, and heme binding in bovine liver catalase were also present in L. seeligeri catalase at the corresponding positions. The recombinant protein contained 488 amino acid residues and had a calculated molecular weight of 55,869. The predicted isoelectric point was 5.0. Enzymatic and genetic analyses showed that there is most probably a single catalase of this type in L. seeligeri. A perfect 21-bp inverted repeat, which was highly homologous to previously reported binding sequences of the Fur (ferric uptake regulon) protein of E. coli, was detected next to the putative promoter region of the L. seeligeri catalase gene.
Collapse
Affiliation(s)
- A Haas
- Institut für Genetik und Mikrobiologie, Universität Würzburg, Germany
| | | | | | | |
Collapse
|
15
|
Craig SP, Yuan L, Kuntz DA, McKerrow JH, Wang CC. High level expression in Escherichia coli of soluble, enzymatically active schistosomal hypoxanthine/guanine phosphoribosyltransferase and trypanosomal ornithine decarboxylase. Proc Natl Acad Sci U S A 1991; 88:2500-4. [PMID: 2006185 PMCID: PMC51260 DOI: 10.1073/pnas.88.6.2500] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The bacterial alkaline phosphatase (phoA) promoter and signal peptide have been used previously to control recombinant expression and secretion of eukaryotic proteins in Escherichia coli. Other reports have shown that this expression system can generate relatively modest levels of active hypoxanthine/guanine phosphoribosyltransferase (HPRT; hypoxanthine phosphoribosyltransferase; IMP:pyrophosphate phosphoribosyltransferase, EC 2.4.2.8), which carries part of the signal peptide but remains in the cytosol of the bacteria. Herein, the phoA promoter without its associated signal peptide is used to regulate expression of the HPRT of Schistosoma mansoni and the ornithine decarboxylase (ODC; L-ornithine carboxy-lyase, EC 4.1.1.17) of Trypanosoma brucei, two enzymes that have been identified as potential targets for antiparasitic chemotherapy. The levels of recombinant expression range from 20% to 60% of the total bacterial protein, and the majority of both recombinant enzymes was soluble. The specific activity for the recombinant trypanosomal ODC was one-third to two-thirds that of the authentic native enzyme and yields were predicted to be 15-30 mg of active enzyme per liter of bacterial culture. The specific activity for the recombinant schistosomal HPRT was equivalent to that for the native enzyme purified from schistosomes and up to 10 mg of enzymatically active HPRT has been purified from a 0.5-liter culture of treated bacteria. These results represent a break-through in recombinant expression of HPRT and ODC.
Collapse
Affiliation(s)
- S P Craig
- Department of Pharmaceutical Chemistry, University of California, San Francisco 94143
| | | | | | | | | |
Collapse
|