Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    The Evolutionary History of Carbamoyltransferases: A Complex Set of Paralogous Genes Was Already Present in the Last Universal Common Ancestor (1999)
    Springer
    Journal of molecular evolution 49 (1999), S. 461-473 
    Details
    ISSN: 1432-1432
    Keywords: Key words: Carbamoyltransferases — ATCase — OTCase — Protein evolution — Gene duplication — Paralogous proteins — Last universal common ancestor — Molecular phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. Forty-four sequences of ornithine carbamoyltransferases (OTCases) and 33 sequences of aspartate carbamoyltransferases (ATCases) representing the three domains of life were multiply aligned and a phylogenetic tree was inferred from this multiple alignment. The global topology of the composite rooted tree (each enzyme family being used as an outgroup to root the other one) suggests that present-day genes are derived from paralogous ancestral genes which were already of the same size and argues against a mechanism of fusion of independent modules. A closer observation of the detailed topology shows that this tree could not be used to assess the actual order of organismal descent. Indeed, this tree displays a complex topology for many prokaryotic sequences, with polyphyly for Bacteria in both enzyme trees and for the Archaea in the OTCase tree. Moreover, representatives of the two prokaryotic Domains are found to be interspersed in various combinations in both enzyme trees. This complexity may be explained by assuming the occurrence of two subfamilies in the OTCase tree (OTC α and OTC β) and two other ones in the ATCase tree (ATC I and ATC II). These subfamilies could have arisen from duplication and selective losses of some differentiated copies during the successive speciations. We suggest that Archaea and Eukaryotes share a common ancestor in which the ancestral copies giving the present-day ATC II/OTC β combinations were present, whereas Bacteria comprise two classes: one containing the ATC II/OTC α combination and the other harboring the ATC I/OTC β combination. Moreover, multiple horizontal gene transfers could have occurred rather recently amongst prokaryotes. Whichever the actual history of carbamoyltransferases, our data suggest that the last common ancestor to all extant life possessed differentiated copies of genes coding for both carbamoyltransferases, indicating it as a rather sophisticated organism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00006569
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The highly thermostable arginine repressor of Bacillus stearothermophilus: gene cloning and repressor–operator interactions (1997)
    Oxford, UK : Blackwell Science Ltd
    Molecular microbiology 25 (1997), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: We report here the cloning of the arginine repressor gene argR of Bacillus stearothermophilus and the characterization and purification to homogeneity of its product. The deduced amino acid sequence of the 16.8-kDa ArgR subunit shares 72% identity with its mesophilic homologue AhrC of Bacilus subtilis. Sequence analysis of B. stearothermophilus ArgR and comparisons with mesophilic arginine repressors suggest that the thermostable repressor comprises an N-terminal DNA-binding and a C-terminal oligomerization and arginine-binding region. B. stearothermophilus ArgR has been overexpressed in E. coli and purified as a 48.0-kDa trimeric protein. The repressor inhibits the expression of a B. stearothermophilus argC–lacZ fusion in E. coli cells. In the presence of arginine, the purified protein binds tightly and specifically to the argC operator, which largely overlaps the argC promoter. The purified B. stearothermophilus repressor proved to be very thermostable with a half-life of approximately 30 min at 90°C, whereas B. subtilis AhrC was largely inactivated at 65°C. Moreover, ArgR operator complexes were found to be remarkably thermostable and could be formed efficiently at up to 85°C, well above the optimal growth temperature of the moderate thermophile B. stearothermophilus. This pronounced resistance of the repressor–operator complexes to heat treatment suggests that the same type of regulatory mechanism could operate in extreme thermophiles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2958.1997.4781845.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Ss-LrpB, a novel Lrp-like regulator of Sulfolobus solfataricus P2, binds cooperatively to three conserved targets in its own control region (2004)
    Oxford, UK : Blackwell Science Ltd
    Molecular microbiology 54 (2004), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Ss-LrpB, a novel Lrp-like DNA-binding protein from the hyperthermophilic crenarchaeon Sulfolobus solfataricus, was shown to bind cooperatively to three regularly spaced targets in its own control region, with as consensus the 15 bp palindrome 5′-TTGYAW WWWWTRCAA-3′. Binding to the border sites occurred with high affinity; the target in the middle proved to be a low affinity site which is stably bound only when both flanking sites are occupied. Ss-LrpB contacts two major groove segments and the intervening minor groove of each site, all aligned on one face of the helix. The operator shows intrinsic bending and is increasingly deformed upon binding of Ss-LrpB to one, two and three targets. Complex formation relies therefore on DNA conformability, protein–DNA and protein–protein contacts. Mobility-shift assays and in gel footprinting indicate that Ss-LrpB and the transcription factors TATA-box binding protein (TBP) and transcription factor B (TFB) can bind simultaneously to the control region. Based on these findings we present a model for the construction of the higher order nucleoprotein complexes and a hypothesis for the autoregulatory process. The latter is based on the concentration-dependent formation of distinct complexes exhibiting different stoichiometries and conformations, which could positively and negatively affect promoter activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2958.2004.04274.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    High resolution contact probing of the Lrp-like DNA-binding protein Ss-Lrp from the hyperthermoacidophilic crenarchaeote Sulfolobus solfataricus P2 (2002)
    Oxford, UK : Blackwell Science Ltd
    Molecular microbiology 45 (2002), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Ss-Lrp, from Sulfolobus solfataricus, is an archaeal homologue of the global bacterial regulator Lrp (Leucine-responsive regulatory protein), which out of all genome-encoded proteins is most similar to Escherichia coli Lrp (E-value of 5.6 e−14). The recombinant protein has been purified as a 68 kDa homotetramer. The specific binding of Ss-Lrp to its own control region is suggestive of negative autoregulation. A high resolution contact map of Ss-Lrp binding was established by DNase I and hydroxyl radical footprinting, small non-intercalating groove-specific ligand-binding interference, and various base-specific premodification and base removal binding interference techniques. We show that Ss-Lrp binds one face of the DNA helix and establishes the most salient contacts with two major groove segments and the intervening minor groove, in a region that overlaps the TATA-box and BRE promoter elements. Therefore, Ss-Lrp most likely exerts autoregulation by preventing promoter recognition by TBP and TFB. Moreover, the results demonstrate profound Ss-Lrp induced structural alterations of sequence stretches flanking the core contact site, and reveal that the deformability of these regions significantly contributes to binding selectivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2958.2002.03136.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Structure of the arginine repressor from Bacillus stearothermophilus (1999)
    [s.l.] : Nature America Inc.
    Nature structural biology 6 (1999), S. 427-432 
    Details
    ISSN: 1072-8368
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] The arginine repressor (ArgR) is a hexameric DNA-binding protein that plays a multifunctional role in the bacterial cell. Here, we present the 2.5 Å structure of apo-ArgR from Bacillus stearothermophilus and the 2.2 Å structure of the hexameric ArgR oligomerization domain with bound ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/8229
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    The arginine operon ofBacillus stearothermophilus: characterization of the control region and its interaction with the heterologousB. subtilis arginine repressor (1996)
    Springer
    Molecular genetics and genomics 252 (1996), S. 69-78 
    Details
    ISSN: 1617-4623
    Keywords: Bacillus stearothermophilus argC gene sequence ; Operator ; Arginine repressor ; Gene regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mechanisms of gene regulation have not yet been extensively studied in thermophilic bacteria. In previous studies we showed that theBacillus stearothermophilus argCJBD gene cluster is subject to specific repression by arginine. Here we report the cloning by colony hybridization, and characterization of the proximal part of theargC gene together with the adjacent control region of the cluster. The promoter was identified by primer extension mapping of theargC transcription startpoint: a sequence overlapping it was found to be similar to the arginine operators ofB. subtilis and to a smaller extent ofE. coli. Use of anargC-lacZ gene fusion revealed that theargC promoter is strongly repressed by the heterologousB. subtilis arginine repressor/activator AhrC inE. coli cells. Mobility shift and DNase I footprinting experiments revealed tight, specific and arginine-dependent binding of this operator-like sequence to purified AhrC. It is there-fore very likely that inB. stearothermophilus the expression of theargCJBD operon is modulated by a repressor that is the thermophilic homologue of AhrC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02173206
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    The arginine operon of Bacillus stearothermophilus: characterization of the control region and its interaction with the heterologous B. subtilis arginine repressor (1996)
    Springer
    Molecular genetics and genomics 252 (1996), S. 69-78 
    Details
    ISSN: 1617-4623
    Keywords: Key wordsBacillus stearothermophilus argC gene sequence ; Operator ; Arginine repressor ; Gene regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mechanisms of gene regulation have not yet been extensively studied in thermophilic bacteria. In previous studies we showed that the Bacillus stearothermophilus argCJBD gene cluster is subject to specific repression by arginine. Here we report the cloning by colony hybridization, and characterization of the proximal part of the argC gene together with the adjacent control region of the cluster. The promoter was identified by primer extension mapping of the argC transcription startpoint: a sequence overlapping it was found to be similar to the arginine operators of B. subtilis and to a smaller extent of E. coli. Use of an argC-lacZ gene fusion revealed that the argC promoter is strongly repressed by the heterologous B. subtilis arginine repressor/activator AhrC in E. coli cells. Mobility shift and DNase I footprinting experiments revealed tight, specific and arginine-dependent binding of this operator-like sequence to purified AhrC. It is therefore very likely that in B. stearothermophilus the expression of the argCJBD operon is modulated by a repressor that is the thermophilic homologue of AhrC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004389670008
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Mutation of gene encoding regulatory polypeptide of aspartate carbamoyltransferase (1981)
    [s.l.] : Nature Publishing Group
    Nature 292 (1981), S. 370-373 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] ATCase catalyses the first reaction specific to pyrimidine biosynthesis, the formation of JV-carbamoyl-L-aspartate from L-aspartate and carbamoylphosphate. In E. coli, ATCase activity is modulated by feedback inhibition by CTP, the end product of the pyrimidine pathway, and activation by ATP, ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/292370a0
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    The structure of unstable constitutive revertants of mutant galOP-308::IS2-I (1980)
    Springer
    Molecular genetics and genomics 179 (1980), S. 391-397 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The isolation and characterization of three unstable and constitutive revertants of mutant galOP-308 of E. coli is described. In this mutant an IS2 element is integrated between the promoter and the first structural gene of the galactose operon, and exerts a strong polar effect on the expression of the three galactose genes. In the three revertants under investigation it was observed that relief of polarity and constitutive expression of the gal-operon were accompanied by the deletion of 90% of the IS2 sequence and of various lengths of the ajdacent sequences including the gal-promoter. We conclude from this result that the transcription termination signals causing strong polarity were located on the deleted part of IS2, and that in our revertants the galactose genes are now under the control of a new promoter which is apparently unstable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00425470
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Integration Host Factor (IHF) modulates the expression of the pyrimidine-specific promoter of the carAB operons of Escherichia coli K12 and Salmonella typhimurium LT2 (1993)
    Springer
    Molecular genetics and genomics 237 (1993), S. 273-286 
    Details
    ISSN: 1617-4623
    Keywords: Integration Host Factor ; carAB ; Pyrimidine regulation ; Escherichia coli K12 ; Salmonella typhimurium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We report the identification of Integration Host Factor (IHF) as a new element involved in modulation of P1, the upstream pyrimidine-specific promoter of the Escherichia coli K12 and Salmonella typhimurium carAB operons. Band-shift assays, performed with S-30 extracts of the wild type and a himA, hip double mutant or with purified IHF demonstrate that, in vitro, this factor binds to a region 300 by upstream of the transcription initiation site of P1 in both organisms. This was confirmed by deletion analysis of the target site. DNase I, hydroxyl radical and dimethylsulphate footprinting experiments allowed us to allocate the IHF binding site to a 38 bp, highly A + T-rich stretch, centred around nucleotide −305 upstream of the transcription initiation site. Protein-DNA contacts are apparently spread over a large number of bases and are mainly located in the minor groove of the helix. Measurements of carbamoyl-phosphate synthetase (CPSase) and β-galactosidase specific activities from car-lacZ fusion constructs of wild type or IHF target site mutants introduced into several genetic backgrounds affected in the himA gene or in the pyrimidine-mediated control of P1 (carP6 or pyrH ±), or in both, indicate that, in vivo, IHF influences P1 activity as well as its control by pyrimidines. IHF stimulates P1 promoter activity in minimal medium, but increases the repressibility of this promoter by pyrimidines. These antagonistic effects result in a two- to threefold reduction in the repressibility of promoter P 1 by pyrimidines in the absence of IHF binding. IHF thus appears to be required for maximal expression as well as for establishment of full repression. IHF could exert this function by modulating the binding of a pyrimidine-specific regulatory molecule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00282809
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...