Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 2.5 X 10(3) base-pair segment of Bacillus sphaericus R DNA cloned in Escherichia coli has previously been shown to carry the functional BspRI modification methylase gene. The approximate location of the gene on this DNA segment and its direction of transcription were established by subcloning experiments. The nucleotide sequence of the relevant region was determined by the Maxam-Gilbert procedure. An open reading frame that can code for a 424 amino acid protein was found. The calculated molecular weight (48,264) of this protein is in fair agreement with previous estimates (50,000 to 52,000). The synthesis of this protein was demonstrated in E. coli minicells. The initiation point of transcription by E. coli RNA polymerase was localized by in vitro transcription experiments. The open reading frame starts 29 base-pairs downstream from the transcription initiation site and it is preceded by a sequence showing extensive Shine-Dalgarno complementarity. Subcloning experiments and translation in minicells suggest that after removal of this translational initiation site, a secondary start site 29 amino acids downstream can also start translation in E. coli, and this shorter protein retains the methylase activity. The overall base composition of the gene and the codon usage indicate a strong preference for A.T base-pairs.
J Mol Biol 1983 Nov 05
PMID:Structure of the Bacillus sphaericus R modification methylase gene. 631 47

Further research on bacteriophage T7 DNA penetration mechanism into E. coli cells during the infection was carried out. The DNA-RNA-hybridization on nitrocellulose filters revealed that in the presence of chloramphenicol the T7 DNA penetration from the virion into a host cell was coupled with its transcription by the bacterial RNA polymerase. The data obtained indicate that in the absence of antibiotics the penetration of a part of T7 genome which correspondes to class II and III genes is coupled with its transcription by a phage-specific RNA polymerase. Along with this the host restriction-modification system when its activity is not inhibited by the phage-induced proteins will be able to cleave the penetrated T7 DNA just after its transcription was accomplished. Considering these data along with our conception on direct involvement of transcription in T7 DNA penetration process during the infection one can suggest that E. coli RNA polymerase molecules which provide the phage DNA transport, are localized at the inner surface of cytoplasmic membrane.
Mol Biol (Mosk)
PMID:[Coupling of bacteriophage T7 DNA penetration with its transcription, during infection]. 635 19

During transformation of B. subtilis cells with the Bsu R restriction-modification system by means of pUB110 plasmid restriction and modification of the plasmid DNA occurs. The effect of restriction on the transformation frequency is relatively weak, bringing about 20-fold decrease only. When using cells of a modifying recipient, the frequency of AR9 phage-mediated transduction of unmodified plasmid DNA is also relatively little decreased. The frequency of transduction by chromosomal markers, under the same conditions, falls much lower.
Mol Gen Genet 1980
PMID:Transformation and transduction of Bacillus subtilis strains with the Bsu R restriction-modification system by means of modified and unmodified DNA of pUB110 plasmid. 677 30

The genetic cassette encoding the DpnII restriction-modification system of Streptococcus pneumoniae gave transcription products of approximately 2.7 and 1.8 kilobases. The larger, mRNA1, covered both of the methylase genes, dpnM and dpnA, and the endonuclease gene dpnB; the smaller, mRNA2, covered only the dpnA and dpnB genes. Transcription of mRNA1 was shown to begin at the translation start site for dpnM, thereby producing an mRNA without any apparent ribosome-binding site for translation of the DpnM methylase. The promoter for mRNA1 was shown by base substitution and deletion analysis to consist of an extended -10 site, TaTGgTATAAT, with no required -35 site. A possible promoter further upstream with close matches to a -35 site and a nonextended -10 site was not used. A survey of 36 proven and putative promoters used by S. pneumoniae revealed that 61% of them contained the full -10 extension, although, other than the dpnM promoter, they matched at a -35 site, as well. It appears that, unlike those found in Escherichia coli, S. pneumoniae promoters frequently require an extended -10 site, and such a site can function naturally without a -35 site.
J Mol Biol 1995 Jul 07
PMID:An extended -10 promoter alone directs transcription of the DpnII operon of Streptococcus pneumoniae. 754 38

EcoP1 modification methylase was radioactively labeled when incubated with S-adenosyl-L-[methyl-3H]methionine in the presence of ultraviolet light. Crosslinking of the enzyme as detected by electrophoresis on sodium dodecyl sulfate-polyacrylamide gel followed by fluorography and autoradiography, was shown to be specific by a number of criteria. More importantly, EcoP1 modification methylase was also radioactively labeled with S-adenosyl-L-[carboxyl-14C]methionine demonstrating that labeling involved binding of the entire AdoMet molecule rather than methylation of the protein. Further, c2 EcoP1 mutant DNA modification methylases which show negligible or very little methylation activity, correspondingly formed a weak or no adduct upon crosslinking. These results suggest that photolabeling of EcoP1 DNA modification methylase occurs at the AdoMet binding site.
Biochem Mol Biol Int 1994 Mar
PMID:Interaction of EcoP1 modification methylase with S-adenosyl-L-methionine: a UV-crosslinking study. 803 13

The DNA of wild-type Streptomyces lividans 66 is degraded during electrophoresis in buffers containing traces of ferrous iron. S. lividans ZX1, a mutant selected for resistance to DNA degradation, simultaneously became sensitive to phi HAU3, a wide-host-range temperate bacteriophage. A DNA fragment conferring phi HAU3 resistance was cloned; it contains a phage resistance gene whose deduced amino acid sequence is similar to the phage lambda Ea59 endonuclease. The S. lividans phi HAU3 resistance does not seem to be a classical restriction-modification system, because no host-modified phages able to propagate on the wild-type strain could be isolated. The cloned fragment did not make the host DNA prone to degradation during electrophoresis, indicating that the two phenotypes are controlled by different genes which were deleted together from the chromosome of ZX1.
Mol Microbiol 1994 Jun
PMID:Streptomyces lividans 66 contains a gene for phage resistance which is similar to the phage lambda ea59 endonuclease gene. 805 30

High-resolution S1 nuclease mapping of mRNA synthesised in vivo, in vitro run-off transcription with RNA polymerase from Streptomyces lividans and gene fusions were used to analyse the transcriptional organization of the SalI restriction-modification system of Streptomyces albus G. The salIR and salIM genes that encode the restriction endonuclease and its cognate methyltransferase constitute an operon which is mainly transcribed from sal-pR1, a promoter located immediately upstream of salIR, with two possible minor promoters further upstream. Another promoter, sal-pM, is within the 3' end of the salIR coding region, and allows expression of the modification gene in the absence of sal-pR1. The sal-pM promoter might be involved in the establishment of modification prior to restriction endonuclease activity. Sequences upstream of the apparent transcriptional start sites for sal-pR1 and sal-pM show similarity with the -10 region of typical vegetatively expressed eubacterial promoters, but appropriately centered -35 regions are absent.
Mol Microbiol 1993 Apr
PMID:Complex transcription of an operon encoding the SalI restriction-modification system of Streptomyces albus G. 831 78

Type I restriction-modification systems bind to non-palindromic, bipartite recognition sequences. Although these enzymes methylate specific adenine residues within their recognition sequences, they cut DNA at sites up to several thousand base-pairs away. We have investigated the mechanism of how EcoR124II, a type IC restriction-modification system, selects the cleavage site. Restriction studies with different DNA constructs revealed that circular DNA requires only one non-methylated recognition sequence to be cut, whereas linear DNA needs at least two such sites. Cleavage of linear DNA is independent of site orientation. Further investigations of the linear substrates revealed a mechanism whereby the double-strand break is introduced between two recognition sequences. We propose a model for the selection of restriction sites by type I enzymes where two EcoR124II complexes bind to two recognition sequences. Lack of methylation at a site stimulates the enzyme to translocate DNA on both sides of the recognition sequence. Thus the two complexes approach each other and, at the point where they meet, they interact to introduce a double-strand break in the DNA.
J Mol Biol 1996 Dec 13
PMID:DNA cleavage by the type IC restriction-modification enzyme EcoR124II. 898 Jun 81

The salIR and salIM genes encode the endonuclease and methyltransferase components of the SalI restriction-modification system from Streptomyces albus G. Expression of the salI genes in Escherichia coli was investigated and major differences with Streptomyces were found. In E. coli there is no detectable expression of the salI R gene due to inactivity of the sal-pR promoter region. In the natural host of the system this region directs transcription of the salI genes as a bicistronic message. In contrast to salIR, salIM is transcribed in the heterologous host from a promoter within the salI DNA. Since sal-pR is not active, the gene cannot be expressed as part of the salI operon. It is probably transcribed from sal-pM, a promoter internal to the operon which allows independent expression of the modification gene in Streptomyces. Replacement of sal-pR by the strong pLac promoter allows expression of salIR in E. coli and enhances expression of salIM. The resulting strain produces about 10 times more endonuclease than a Streptomyces clone containing the SalI system under the control of sal-pR.
Mol Gen Genet 1996 Nov 27
PMID:Comparative analysis of expression of the SalI restriction-modification system in Escherichia coli and Streptomyces. 900 89

BsoBI is a type II restriction enzyme found in Bacillus stearothermophilus JN209 that recognizes the symmetric sequence 5'-CYCGRG-3' (Y=C or T; R=A or G) and cleaves between the first and second base to generate a four-base 5' extension. The cloning and sequencing of BsoBI restriction-modification system has been described by Ruan et al. [Mol. Gen. Genet. 252 (1996) 695-699]. Here we report the overexpression of BsoBI restriction endonuclease gene in E. coli by insertion of the endonuclease gene into an expression vector pRRS. The recombinant BsoBI was purified to homogeneity and its N-terminus sequence was determined. It has the same N-terminal aa sequence as the native enzyme. The constitutive expression of BsoBI from pRRS is lethal to E. coli in the absence of the cognate methylase. The bsoBIR gene was mutagenized with either hydroxylamine or by error-prone polymerase chain reaction in vitro and transferred into E. coli via plasmid vectors in the absence of the cognate methylase. Surviving transformants were selected that carry BsoBI variants which lost endonuclease activity. DNA sequencing of the mutant alleles revealed that G123, D124, D212, D246, E252 and H253 are important residues for enzymatic activity. An electrophoretic mobility shift assay was used to identify binding-proficient and cleavage-deficient variants. Seven variants I95M&D124Y, G123R, D212N, K207R&D212V, D246N, D246G and E252K can still bind DNA despite the loss of cleavage activity. Thus, residues D124, D212, D246 and E252 may be located near or within the catalytic center, and are likely involved in metal ion binding.
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PMID:Overexpression of BsoBI restriction endonuclease in E. coli, purification of the recombinant BsoBI, and identification of catalytic residues of BsoBI by random mutagenesis. 909 56


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