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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Six types of plasmid-mediated carbenicillinases can be distinguished on the basis of their substrate profiles, molecular mass isoelectric values and immunological properties. As yet, no structural classification has been attempted for these enzymes at the molecular level. We have isolated the PSE-4 structural gene responsible for carbenicillinase production in Pseudomonas aeruginosa strain Dalgleish and studied its expression in E. coli. A detailed physical map of the cloned fragment and the construction of deletion mutants permitted the precise localization of the PSE-4 structural gene. Various restriction endonuclease fragments known to be flanking or internal to the PSE-4 bla gene were used as DNA probes and tested for homologous sequences in other beta-lactamase genes. A collection of three restriction fragment probes internal or delimiting the PSE-4 structural gene were hybridized with purified plasmid DNA coding for 18 other beta-lactamases. Under high stringency conditions, only the PSE-1, CARB-3 and CARB-4 genes cross-hybridized with PSE-4; while one of the probes tested hybridized solely with CARB-3. Further analysis indicated that the PSE-1, PSE-4, CARB-3 and CARB-4 bla genes are related and could presumably have evolved from a common progenitor.
Mol Cell Probes 1989 Jun
PMID:Development of gene probes and evolutionary relationships of the PSE-4 bla gene to plasmid-mediated beta-lactamases of gram-negative bacteria. 278 7

The host-vector system for efficient expression of the cloned genes under the control of transactivated promoter p'R of bacteriophage lambda has been elaborated. The Q protein activating p'R promoter is coded by the defective prophage constructed in vitro by means of excision of the late phage genes between the distant sites of the restriction endonuclease MluI and change of the central SalI fragment carrying the kill gene for the kanamycin resistance gene. The general recombination system is impaired during the change, thus the bacteriophage DNA can be obtained from the induced RecA cells as a plasmid DNA. The induction of the prophage results in a sharp increase of beta-lactamase synthesis (30% of soluble cell protein) under the control of p'R promoter in a plasmid derived of pBR322.
Mol Gen Mikrobiol Virusol 1988 Aug
PMID:[Transactivation of p'R promoter of phage lambda]. 297 62

A systematic study of the specificity of insertion of the transposable element IS1 into small defined-sequence plasmids (pBR322 and derivatives) was conducted to determine the features of the DNA sequence that influence target site selection. We have physically mapped several collections of independent insertions of IS1 into these plasmids and have determined: (1) that about 80% of all insertions occur in the DNA segment (about 200 base-pairs) between the unique EcoRI site of pBR322 and the beginning of the beta-lactamase gene, one of the two regions of high A + T density in this plasmid; (2) that there is a strong orientation effect in this region (almost all IS1 insertions are in one orientation) that depends on both the pBR322 sequence and the environment of the transposon in the donor molecule; and (3) that the orientation effect does not depend on the strong transcription that is directed through this region in pBR322. Furthermore, we have found that insertion of a poly(dA X dT) segment into pBR322 creates an artificial hotspot for IS1 insertion, even though it is not as attractive for insertion as the above-mentioned major hotspot. Our observations suggest that an interplay between several properties of the target sequences and the sequence environment of the donor transposon is responsible for the observed specificity of position and orientation. One of the possibilities discussed here is that preferred "entry-sites", or "signal" sequences, for the transposition complex play a major role in determining the positions and orientations of IS1 insertions.
J Mol Biol 1985 Oct 05
PMID:Specificity of insertion of IS1. 299 52

The lipase (lip) gene of Staphylococcus hyicus was used to study the expression of the Escherichia coli beta-lactamase (bla) gene in S. carnosus. The bla gene, devoid of its promotor and most of the signal sequence, was fused to the lip structural gene at various positions. A set of 11 secretion vectors (pLL beta 1 to pLL beta 11) was isolated and analysed. All secretion vectors caused beta-lactamase production and activity in S. carnosus. However, the amount of hybrid proteins secreted was influenced by the length of the NH2-terminal lipase portion. An increased concentration, comparable to that of the native lipase, of secreted lipase/beta-lactamase hybrid proteins was only found when the lipase portion of the construct comprised more than 101 amino acids of the NH2-terminal region of the lipase preprotein; the proposed lipase signal peptide is 36 amino acids long. If the hybrid proteins constructed contained 101 or less amino acids of the NH2-terminal lipase preprotein, only low amounts of secreted hybrid proteins were detectable and a significant portion of the hybrid proteins and beta-lactamase activity was found in the cellular fraction. The results indicate that the lipase possesses adjacent to the signal peptide a peptide domain that is essential for the secretion of the lipase/beta-lactamase hybrid proteins.
Mol Gen Genet 1986 Jul
PMID:Studies on lipase directed export of Escherichia coli beta-lactamase in Staphylococcus carnosus. 301 41

We have isolated several insertions of the transposable element IS1 into the proximal promoter (P3) of the beta-lactamase gene of plasmid pBR322, which do not abolish resistance to ampicillin. Using a transcription termination module (omega), we have shown that the gene can be expressed from hybrid promoters, created by the insertion of IS1. The terminal inverted repeats of IS1 carry sequences partially homologous to the "-35" consensus region. Splicing either of these sequences to the existing "-10" region of the beta-lactamase promoter by transposition of IS1 at the proper distance results in the formation of an active hybrid promoter. This interpretation was confirmed by transcription studies in vitro. Gene expression from the hybrid promoters was found to be less efficient than from P3. However, the orientation of IS1 that contributes a "-35" with the greater homology to the known "-35" consensus sequence is significantly more efficient than the other. In addition, we were able to assign a strong determinant of IS1 polarity to a 254 base-pair internal segment of IS1. An examination of the ends of many insertion sequences leads us to expect that the phenomenon described here may occur with several of these transposable elements, and may have an unexpected evolutionary significance.
J Mol Biol 1986 Oct 05
PMID:Functional promoters created by the insertion of transposable element IS1. 302 82

It was found that CRP-cAMP-recognized sequences in DNA being suggested as GTGN7-11CAC (with variability both in domain's structures and in spacer's length) are located non-randomly in promoters. In CRP-cAMP-stimulated promoters they lie upstream the "-35" box and are separated from it by a whole number of DNA turns, whereas in CRP-cAMP-repressed ones they are located downstream "-35" in a half-whole-turn-number distance. Several CRP-, SOS- and NR1-sites in the phi X174 DNA sequence were found and a few new promoters were deduced from it. PCRP1 lies within gene F and has both CRR and ntrC sites and one SOS-operator, PCRP3 (in gene A) has a CRP site which overlaps with the SOS-operator, PA and PCRP2 (in gene G) have sCRP and PD has a stringent discriminator. Four promotors, PCRP1, PCRP2, PA and PB are cloned in the pBR322 plasmid. For cloned PCRP1 the activation by exogenous cAMP and the SOS-induction by the mitomycin C were observed in vivo in pVYB215-containing cells by increasing the levels of beta-lactamase up to 27-fold. The new gene L of the phi X174 is deduced from the DNA sequence. It has two start points, overlaps the gene F inside it and codes for peptides 23 or 19 amino acids in length. These lethal peptides have strong homology in sequence to the cellular protein sulA(sfiA) of E. coli, and L* can cause observed filamentation and death of pVYB215- bearing cells after PCRP1 induction. In the A and A* protein sequences two domains "helix-turn-helix" were found that are homologous to those in CRP and repressors; this makes possible the competition between A* and CRT for its DNA sites that also have some homology. The model of the phi X174 infection cycle control and mechanisms of DNA recognition by CRP-CAMP are discussed. PCRP1 is the first promotor controlled by both three global regulons of E. coli cell.
Mol Biol (Mosk)
PMID:[Minor promoters of phage phi X174 are controlled by CRP-cAMP, lexA, glnG and several other common common regulatory systems of the host cell]. 303 74

Molecular cloning of DNA fragments between 1.5 and 8 kb from BamHI, EcoRI, HindIII, SalI, or Sau3A digests permitted the isolation of structural genes coding for TEM-1, ROB-1, OXA-1, OXA-3, OXA-4, OXA-5, PSE-1, PSE-2, PSE-3, PSE-4, CARB-3, CARB-4, AER-1, and LCR-1 beta-lactamases. Ampicillin-resistant clones were selected and it was confirmed that they contained the respective beta-lactamase genes by isoelectric focusing. Detailed physical maps of 14 different recombinant plasmids were constructed using 8 restriction endonucleases. Plasmid deletions and lacZ fusions were used to localize the beta-lactamase structural genes. DNA probes were constructed for the TEM-1, ROB-1, OXA-1, and PSE-1 genes. Under conditions of high stringency, hybridization was observed between the genes for TEM-1 and TEM-2 or TLE-1, OXA-1 and OXA-4, and PSE-1 and PSE-4 or CARB-3, while the ROB-1 gene probe showed no cross-hybridization. Such bla gene probes should facilitate studies of beta-lactamase molecular epidemiology.
Mol Gen Genet 1987 Feb
PMID:Molecular cloning and DNA homology of plasmid-mediated beta-lactamase genes. 303 34

Unusual DNA rearrangements involving the prokaryote mobile genetic element IS30 have been identified. In order to study the potential mechanisms for the reactivation of a gene after IS element insertion, IS30 was introduced between the lacUV5 promoter and the galK gene of the multicopy plasmid pFR100. In this plasmid terminators of RNA transcription in the sequence of IS30 prevent expression of the galK gene from the lacUV5 promoter. A number of independently isolated mutant plasmids re-expressing the galK gene were studied and shown to be tandemly repeated dimers of the original plasmid. However, the two copies of IS30 were tandemly repeated at one of the original sites of insertion, while at the other site IS30 and three base pairs were missing. The repeated copies of IS30 were separated by two base pairs, the same as those originally flanking the elements. An apparently identical mechanism generated cointegrates between a derivative of plasmid pFD51 carrying IS30 upstream of a promoterless galK gene and a derivative of plasmid pACYC177 carrying IS30 inserted into the beta-lactamase gene. This arrangement brought the galK gene under the control of the beta-lactamase promoter of pACYC177. A mechanism involving aborted conservative transposition of IS30 is discussed as a possible route for the generation of these novel cointegrates. In a third experiment we isolated an insert of IS30 which was also two base pairs away from an already resident IS30 element. This insertion of IS30 created a strong promoter of RNA transcription, which has the potential to increase the expression of the transposase in the downstream copy of the element.
Mol Gen Genet 1987 May
PMID:Novel rearrangements of IS30 carrying plasmids leading to the reactivation of gene expression. 303 99

Internal deletions close to the C-terminus of the Escherichia coli penicillin binding protein 5 (PBP5, DacA) have defined the C-terminal 18 residues of the protein as essential for membrane binding. This C-terminal sequence is capable of forming a strongly amphiphilic alpha-helix. In this paper we show that the PBP5 amphiphilic helix is able to anchor the periplasmic TEM-beta-lactamase to the inner membrane. In addition, we have demonstrated that mature PBP5 (lacking the N-terminal signal sequence) possesses the ability to bind to the membrane from a soluble form of the protein, showing that translocation across the membrane is unnecessary for anchoring to be established.
Mol Microbiol 1988 Sep
PMID:Analysis of the membrane-binding domain of penicillin-binding protein 5 of Escherichia coli. 305 22

A mutant of Escherichia coli, in which signal peptidase I synthesis can be regulated, was constructed. The mutant was used to study the effects of signal peptidase I limitation on the synthesis and efficiency of processing of two proteins: the periplasmic E. coli TEM-beta-lactamase and Bacillus licheniformis alpha-amylase, which also accumulates in the periplasm of E. coli. Signal peptidase I limitation resulted in reduced rates of processing of pre-beta-lactamase and in strong inhibition of synthesis of alpha-amylase. The data suggest that beta-lactamase is processed post-translationally and that an intimate relationship exists between the synthesis and processing of alpha-amylase.
Mol Gen Genet 1988 Sep
PMID:Synthesis and processing of Escherichia coli TEM-beta-lactamase and Bacillus licheniformis alpha-amylase in E. coli: the role of signal peptidase I. 306 81


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