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M A Tukalo

Publications and source records attributed to M A Tukalo.

At least 19 recordsLinked to original sources
PubMed1999

[Comparative study of the reactability of phosphoric acid residues in tRNA(Ser) and tRNA(Leu) from Thermus thermophilus].

The reactivity of phosphates in the Thermus thermophilus tRNA(Ser) (GCU) and tRNA(Leu) (CAG) was studied using the ethylnitrosourea modification. It was shown that phosphates of nucleotides 58-60 (T loop), 20-22 (D loop), and 48 (at the junction of the variable and T stems) were poorly modified in both tRNAs. The most pronounced differences in the reactivity were observed for phosphates at the junctions of the variable stem with T-stem (47q, 49) and anticodon stem (45). This indicates differences in orientations of the long variable arm relative to the backbone in the tRNAs studied.

Anticodon↗
PubMed1998

[Comparative analysis of interaction sites of Thermus thermophilus and Escherichia coli tRNA(Tyr) with homologous aminoacyl-tRNA synthetases by means of chemical modification and nuclease hydrolysis].

A nucleotide sequence of tRNA(Tyr) from the extreme thermophile Thermus thermophilus HB-27 living at 75 degrees C was determined. It is 86 nt long and shares a 52% homology with tRNA(Tyr) from Escherichia coli. A comparative analysis of the interaction sites of tRNA(Tyr) from T. thermophilus and E. coli with the cognate aminoacyl-tRNA synthetases was accomplished by the chemical modification and nuclease hydrolysis approaches. The tRNA(Tyr) was shown to interact with the cognate enzyme in the anticodon stem (on the 5'-side), in the anticodon, in the variable stem and loop (on the 5'-side), and in the acceptor stem (on the 3'-side). These regions are located in the variable stem of the L-form. It was demonstrated that, upon forming the complex E. coli tRNA(Tyr)-cognate synthetase, endonuclease V1 induces additional cleavages of phosphodiester bonds on the 3'-side of the anticodon stem and on the 5'-side of the T-stem. This implies that tRNA may change its conformation when it interacts with the enzyme.

Amino Acyl-tRNA Synthetases↗
PubMed1995

Cocrystallization of lysyl-tRNA synthetase from Thermus thermophilus with its cognate tRNAlys and with Escherichia coli tRNAlys.

Lysyl-tRNA synthetase from Thermus thermophilus has been cocrystallized with either its cognate tRNAlys or Escherichia coli tRNAlys using ammonium sulfate as precipitant. The crystals grow from solutions containing a 1:2.5 stoichiometry of synthetase dimer to tRNA in 18-22% ammonium sulfate in 50 mM Tris-maleate buffer at pH 7.5. Both complexes form square prismatic, tetragonal crystals with very similar unit cell parameters (a = b = 233 A, c = 119 A) and diffract to at least 2.7 A resolution. However the homocomplex is of space group P42(1)2 and the heterocomplex of space group I422.

Crystallization↗
PubMed1993

Refined crystal structure of the seryl-tRNA synthetase from Thermus thermophilus at 2.5 A resolution.

The three-dimensional structure of the seryl-tRNA synthetase from Thermus thermophilus has been determined and refined at 2.5 A resolution. The final model consists of a dimer of 421 residues each and 190 water molecules. The R-factor is 18.4% for all the data between 10 and 2.5 A resolution. The structure is very similar to that of the homologous enzyme from Escherichia coli, with an r.m.s. difference of 1.5 A for the 357 alpha-carbon atoms considered equivalent. The comparison of the two structures indicates increased hydrophobicity, reduced conformational entropy and reduced torsional strain as possible mechanisms by which thermostability is obtained in the enzyme from the thermophile.

Amino Acid Sequence↗
PubMed1992

A new crystal form of the complex between seryl-tRNA synthetase and tRNA(Ser) from Thermus thermophilus that diffracts to 2.8 A resolution.

Two distinct complexes between seryl-tRNA synthetase and tRNA(Ser) from Thermus thermophilus have been crystallized using ammonium sulphate as a precipitant. Form III crystals grow from solutions containing a 1:2.5 stoichiometry of synthetase dimer to tRNA. They are of monoclinic space group C2 with unit cell dimensions a = 211.6 A, b = 126.8 A, c = 197.1 A, beta = 132.4 degrees and diffract to about 3.5 A. Preliminary crystallographic results show that the crystallographic asymmetric unit contains two synthetase dimers. Form IV crystals grow from solutions containing a 1:1.5 stoichiometry of synthetase dimer to tRNA. They are of orthorhombic space group P2(1)2(1)2(1) with unit cell dimensions a = 124.5 A, b = 128.9 A, c = 121.2 A and diffract to 2.8 A resolution. Preliminary crystallographic results show that these crystals contain only one tRNA molecule bound to a synthetase dimer.

Crystallization↗
PubMed1992

Crystallization of the seryl-tRNA synthetase-tRNA(Ser) complex from Thermus thermophilus.

The complex between seryl-tRNA synthetase and its cognate tRNA from the extreme thermophile Thermus thermophilus has been crystallized from ammonium sulphate solutions. Two different tetragonal crystal forms have been characterized, both diffracting to about 6 A using synchrotron radiation. One form grows as large bipyramids and has cell dimensions a = b = 127 A, c = 467 A, and the second form occurs as long, thin square prisms with cell dimensions a = b = 101 A, c = 471 A. Analysis of washed and dissolved crystals demonstrates the presence of both protein and tRNA.

Crystallization↗
PubMed1991

Immuno-chemical non-cross-reactivity between eukaryotic and prokaryotic seryl-tRNA synthetases.

Monospecific polyclonal antibodies (pAbs) against highly purified bovine seryl-tRNA synthetase (SerRS, EC 6.1.1.1) were prepared and their specificity tested. The interactions of pAbs with SerRS from different organisms were investigated by protein immunoblotting and ELISA methods. pAbs inhibit eukaryotic SerRS aminoacylating activity and exert no effect on SerRS activity from prokaryotes. It is proposed that prokaryotic and eukaryotic SerRS evolve from different ancestor genes.

Animals↗
PubMed1990

Crystals of seryl-tRNA synthetase from Thermus thermophilus. Preliminary crystallographic data.

Crystals have been obtained of seryl-tRNA synthetase from the extreme thermophile Thermus thermophilus, using mixed solutions of ammonium sulphate and methane pentane diol. The crystals are very stable and diffract to at least 2 A. The crystals are monoclinic (space group P21) with cell parameters a = 87.1 A, b = 126.9 A, c = 63.5 A and beta = 109.7 degrees.

Amino Acyl-tRNA Synthetases↗
PubMed1990

[Determination of interacting segments of tRNA(Leu) from cow mammary glands with homologous aminoacyl-tRNA-synthetase by a chemical modification method].

The interaction of the cow mammary gland tRNA(IAGLeu), having a long variable loop, with the cognate aminoacyl-tRNA synthetase has been studied by the alkylation with ethylnitrosourea. It was shown that leucyl-tRNA synthetase protects from alkylation 3'-phosphates of the nucleotides 12-13 in D-loop, 23-24 in D-stem and 37-43 in the anticodon arm of tRNA(IAGLeu). All regions of interaction with the aminoacyl-tRNA synthetase are located in the same plane of tRNA whereas the long variable loop is in another plane.

Alkylation↗
PubMed1988

[A study of the conformation of tRNA(IAGLeu) from the cow mammary gland using chemical modification methods].

The nucleosides of tRNA(IAGLeu) (with a long variable loop) from the cow mammary gland included in formation of the three-dimensional structure have been analysed by the chemical modification methods. Exposed guanosine and cytidine residues were detected by means of dimethylsulfate, whereas diethylpyrocarbonate was used to detect exposed adenosine residues. The low level of the modification was characteristic of guanosine residues in positions 10 (m2G), 13, 15, 23, 24, 29, 30, 47 H, 51, 52, 53, 57; of cytidine residues in positions 48 (m5C), 56 and those involved in Watson--Crick pairing; of adenosine residues in positions 14, 22, 31, 42, 59, 64. Most bases of tRNA(IAGLeu) thus detected are similarly located in the yeast tRNA(Phe) molecule, which suggests a common role of these bases in the formation of the spacial structure of both tRNAs.

Animals↗
PubMed1987

trans-Diamminedichloroplatinum(II), a reversible RNA-protein cross-linking agent. Application to the ribosome and to an aminoacyl-tRNA synthetase/tRNA complex.

A new approach allowing detection of contact points between RNAs and proteins has been developed using trans-diamminedichloroplatinum(II) as the cross-linking reagent. The advantage of the method relies on the fact that the coordination bonds between platinum and the potential acceptors on proteins and nucleic acids (mainly S of cysteine or methionine residues; N of imidazole rings in histidine residues; N7 of guanine, N1 of adenine, and N3 of cytosine residues) can be reversed, so that the cross-linked oligonucleotides or peptides in contact within a complex can be analyzed directly. The method was worked out with the ribosome from Escherichia coli and the tRNAVal/valyl-tRNA synthetase system from the yeast Saccharomyces cerevisiae. In the first system the platinum approach permitted detection of ribosomal proteins cross-linked to 16S rRNA within the 30S subunits (mainly S18 and to a lower extent S3, S4, S11, and S13/S14); in the second system major oligonucleotides of tRNAVal cross-linked to valyl-tRNA synthetase were detected in the anticodon stem and loop, in the variable loop, and in the 3' terminal amino acid accepting region. These results are discussed in light of the current knowledge on ribosome and tRNAs and of potential applications of the methodology.

Amino Acyl-tRNA Synthetases↗
PubMed1986

[Determination of phosphate residues participating in the formation of the spatial structure of tRNA- Leu IAG from cow mammary glands].

The phosphates of the tRNA-Leu IAG from cow mammary gland (tRNA which has a long variable loop) participating in the formation of three-dimensional structure were studied by alkylation with ethylnitrosourea and methylnitrosourea. A low degree of modification was observed for the phosphates of the following nucleotides: 7, 8, 9, 10 (at the bend site between the acceptor and D-stem); 18, 19, 20A and 21 in the D-loop; 47H and 49 at the joint of variable and T-stem; 57, 58 and 59 in the T-loop.

Animals↗
PubMed1984

[Primary structure of tRNA2Leu from the bovine udder. Determination of the oligonucleotide structure of the pyrimidyl-RNAse hydrolysate of tRNA2Leu by microspectrophotometric methods].

tRNA2Leu from cow mammary gland has been degraded with pancreatic ribonuclease, and the fragments obtained were separated by DEAE-cellulose micro-column chromatography in 7 M urea at pH 7,5. Rechromatography was performed on a DEAE-cellulose micro-column at pH 3,7 and also on Dowex 1 X 2 in a formiate system. Nucleotide analysis was carried out with the aid of T2-RNase hydrolysis followed by chromatography on anion-exchanger AG 1 X 8. Nucleosides were separated on Aminex A-6 at pH 9,8. 15 minor components were shown to be present: T, 2 psi, 2Um, 2D, m5C, ac4C, m1G, 2m2G, m22G, m1A and N, the N is not identified so far. The structure of oligonucleotides was established by terminal analysis, hydrolysis with T1-RNase and also using incomplete hydrolysis by the snake venom phosphodiesterase.

Animals↗
PubMed1984

[Primary structure of tRNA2Leu of bovine mammary gland. Oligonucleotides of T1-RNAse hydrolysate. Reconstruction of a total nucleotide sequence].

The oligonucleotides obtained by digestion of tRNA2Leu from cow mammary gland with T1 RNase were separated by micro-column chromatography on DEAE-cellulose in 7 M urea at pH 7,5 and 3,7, and in addition on Dowex 1 x 2. The digest consisted of 18 individual components, the larger being a tridecanucleotide. Micro-column chromatography of nucleotides on anion-exchanger AG 1 x 8 and nucleosides on Aminex A-6 was used to determine the base composition of the oligonucleotides. The oligonucleotide structure was established using terminal analysis, hydrolysis by pancreatic and U2-RNases and incomplete hydrolysis by snake venom phosphodiesterases. The total primary structure of tRNA2Leu was derived from overlapping fragments isolated after its complete hydrolysis with pancreatic and T1 RNase and using data obtained on S1-nuclease digestion of tRNA. The methods of rapid gel-sequencing were also employed for checking the nucleotide sequence of tRNA2Leu from cow mammary gland.

Animals↗
PubMed1983

[Isolation and characterization of individual tRNA Leu 1,2,and 4 from the bovine udder].

tRNA-Leu 1, tRNA-Leu 2 and tRNA-Leu 4 were isolated from a lactating cow mammary gland by combination of several chromatographic methods. Chromatography on a Sepharose 4B column with a reverse salt gradient was used as the first step. Individual tRNAsLeu were further purified by RPC-5 column chromatography at pH 4.5 and 7.5. For isolation of tRNA-Leu 2 a RPC-5 column was additionally used at pH 3.3 in the presence of 7 M urea. Using micro-column chromatography of Ti-RNAases digests, it was demonstrated that tRNA-Leu 1 and tRNA-Leu 2+ are similar in their primary structure and differ essentially from tRNA-Leu 4.

Animals↗