PubMed Health⌕ Search

Biomedical subjects

R S Esipov

Publications and source records attributed to R S Esipov.

13 recordsLinked to original sources
PubMed1999

[The dependence of the E.coli gene expression level on the structure of the translation initiation region (TIR). IV. Distal complementary TIR interactions with the mRNA coding region].

To evaluate the effect on translation of distal regions of the encoding mRNA part capable of the complementary binding to the ribosome binding site (RBS), a series of plasmids were constructed containing fragments inserted into the il3 gene and determining secondary interactions in mRNA. A comparison of the levels of the in vivo gene expression showed that the complementary interactions of the translation initiation region (TIR) with distal regions of the mRNA encoding part affect translation. The effectiveness of these interactions decreased with an increase in the distance between the RBS and the complementary mRNA region, whereas the secondary structure formed by the TIR and the adjacent mRNA region was more stable despite the presence of regions in mRNA capable of forming energetically more favorable structures involving these elements.

Codon, Initiator↗
PubMed1997

[Recombinant proteins containing amino acid sequences of two ectatomin chains].

Artificial genes for chains A and B of ectatomin, an Ectatomma tuberculatum ant toxin, were obtained by chemical and enzymic synthesis and cloned into new plasmid vectors. Expression plasmids with the genes of hybrid proteins were constructed containing human interleukin-3 or its terminal 63-mer fragment as well as chains A and B of ectatomin, which are linked via a region containing the cleavage site of specific protease, enterokinase (hybrid proteins IL3ETOXA, IL3ETOXB, ILETOXA, and ILETOXB). Escherichia coli producer strains providing a high yield of IL3ETOXA and IL3ETOXB proteins as inclusion bodies were obtained.

Amino Acid Sequence↗
PubMed1997

[Relation between the level of E. coli gene expression and the structure of translation initiation region (TIR). III. Sites of complementary interaction of TIR with 16S rRNA].

Potential sites of the complementary interaction of the translation initiation region (TIR) with 16S rRNA are revealed, and the role of these sites in the gene expression level is studied. The high expression level of a gene depends not only on the complementary interaction of TIR with 16S rRNA in sites proximal to the start codon [anti-Shine-Dalgarno (ASD) (delta G > -8 to -10 kcal/mol) and downstream box (DB)] and located at the -15 to +20 mRNA region but also on complementary interactions in distal sites of the untranslated branch of TIR (mTIR). Among them, the UB (upsteam box) 1 site, complementarily interacting with the exposed 452-490 segment of the 440-490 loop of 16S rRNA, may be located in the -15 to -50 mTIR segment. In the -50 to -70 mTIR segment may be located UB2 and UB3 sites, which interact with the exposed segment 478-488 of the 440-490 loop and segment 520-532 of the 520-540 loop of 16S rRNA, the UB3 site being much more efficacious. The high expression level requires that the total free energy of complementary interactions of UB1, UB2, and UB3 sites with 16S rRNA exceeds -20 kcal/mol.

Base Sequence↗
PubMed1996

[Mechanism of action of the plant hormone jasmonate. 1. Jasomonate-interacting proteins that regulate transcription of the p. pinII potato gene].

A fragment containing the regulatory region of the p. pinII gene was isolated from potato DNA by polymerase chain reaction. Interactions of this DNA region with jasmonate determines the transcriptional activation. The isolated DNA fragment was cloned into the pTE2pb plasmid, which was used for preparing an affinity sorbent. Using this sorbent, four proteins were isolated from the total protein capable of desorption at physiological concentration of jasmonate. These proteins are likely to be subunits of two transcription repressors, whereas jasmonate serves as an inducer. Three sequences of the regulatory regions (boxes G, I, and III) are binding sites for repressors; similar sequences were found in various plant genes activated by jasmonate.

Base Sequence↗
PubMed1995

[Dependence of the level of gene expression in E. coli on the structure of the translation initiation segment (TIR). I. Primary structure of TIR].

The comparison of expression levels of two genes-interleukin-3 (il3) and epidermal growth factor connected to leader peptide of OmpF (lompegf)-was carried out using specially constructed plasmids contained various structures of translational enhancers. It was shown that besides already known binding sites from mRNA translation initiation region (TIR) to 16S rRNA (SD, UB1 and DB), there is additional binding site of TIR disposed from -30 to -60 nt upstream of start codon AUG (UB2) having significant increasing effect on translation initiation and correspondingly on expression level.

Bacterial Outer Membrane Proteins↗
PubMed1995

[Dependence of the level of gene expression in E. coli on the structure of the translation initiation segment (TIR)].

The expression levels of genes that are transcribed to give mRNAs with identical leader sequences and even with identical extended coding regions may differ considerably. In order to determine the mechanism of this phenomenon, secondary structures of some mRNAs synthesized from a series of expression plasmids were studied. It was shown that the effect of the mRNA secondary structure in the translation initiation region on the initiation efficiency is due not only to the hairpin formation in this region but also to long-range interactions. When complementary structures tighter than those resulted from the interaction of regions SD, UB1, UB2, and DB with 16S rRNA are formed, the efficiency of the translation initiation and, consequently, the expression level decrease.

Base Sequence↗
PubMedDate not supplied

[Methods of preparation of recombinant proteins-cytokines. IV. Renaturation of recombinant human interleukin-3].

Renaturation of recombinant human interleukin-3 produced as inclusion bodies in the transformed cells of Escherichia coli was studied and optimized. Importance was shown of removing from the protein solution the hydrophobic cellular components causing irreversible aggregation of the protein under renaturation conditions. An effect of pH on the secondary structure of the denatured protein was revealed by CD spectroscopy. It was thereby found that at pH 8.5, which is the optimal value for denaturation, the protein has the secondary structure most close to the native one. The isolation according to the scheme proposed allows preparation of interleukin-3 in 50% yield with 99% purity and biological activity 2 x 10(7) U/mg.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

[Chemical and chemico-enzymatic synthesis of alpha-thiotriphosphate nucleosides].

New methods of chemical and chemoenzymatic synthesis of nucleoside 5'-thiophosphates and 5'-alpha-thiotriphosphates are developed. The 5'-alpha-thiotriphosphates are used as substrates both in template-dependent enzymatic PCR synthesis and in a T7-RNA transcription polymerase system. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2003, vol. 29, no. 6; see also http://www.maik.ru.

Base Sequence↗
PubMedDate not supplied

[Recombinant thymosin alpha1].

An artificial gene encoding thymosin alpha1 was obtained by the chemoenzymatic synthesis and cloned into Escherichia coli. An expressing recombinant plasmid containing the hybrid protein gene, which encodes amino acid sequences of thymosin alpha1 and the Saccharomyces cerevisiae intein Sce VMA, was constructed. The expression of the hybrid protein from the resulting hybrid gene in E. coli, the properties of the resulting hybrid protein, and the conditions for its nonenzymatic cleavage to thymosin alpha1 were studied. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 5; see also http: // www.maik.ru.

Amino Acid Sequence↗
PubMedDate not supplied

[Biotechnological synthesis of ribavirin. Effect of ribavirin and its various combinations on the reproduction of Vaccinia virus].

The biotechnological method of synthesis of ribavirin, vidarabin, and 6-azauridine by the use of immobilized recombinant enzymatic preparations of nucleoside phosphorylase was improved. The effect of ribavirin and its combinations with the other synthesized nucleosides on the reproduction of Vaccinia virus was studied using cultures of Vero cells. The combination of ribavirin and vidarabin was shown to provide an antiviral effect at lesser concentrations than when these compounds were taken separately. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 6; see also http://www.maik.ru.

Animals↗
PubMedDate not supplied

[Using of 4-thiouridine and 4-thiothymidine for pyrimidine nucleoside phosphorylase studing].

4-Thiouridine and 4-thiothymidine were developed as efficient substrates for spectrophotometric determination of uridine phosphorylase and thymidine phosphorylase activity. 4-Thiouridine has maximum absorbance at 330 nm (pH 7.5). The change in extinction coefficient for 4-thiouridine/4-thiouracil, deltaepsilon is 3000 M(-1) x cm(-1). It appeared that 4-thiouridine is a good substrate for uridine phosphorylase with Michaelis-Menten constant 130 microM and kcat 49 s(-1). In the case of 4-thiothymidine/4-thiothymine deltaepsilon is even larger: 5000 M(-1) x cm(-1) at 336 nm.

Magnetic Resonance Spectroscopy↗