Mikhailo Tukalo

Mikhailo Arsentiyovich

українська версія
english version

Date of birth: June 2, 1951. Degree: Taras Shevchenko Kyiv National University, M.S. in Biochemistry (1968-1973). Dsc in Molecular Biology, year awarded: 1989. Degrees: Senior Researcher, year awarded: 1988.

Place of work: Institute of Molecular Biology and Genetics NAS of Ukraine. Present position: Head of Department of Protein Synthesis Enzimology.

Honours and awards: 1986, State Prize of Ukraine in Science and Technique for contribution to Molecular Biology through research on the regulation of protein biosynthesis.

Grants: 1992-1995, NATO Collaborative Research Grant; 1995-2000, Howard Hughes Medical Institute International Research Grant; 2001-2003, INTAS Collaborative Research Grant.

My general research interest is the structural basis of the RNA- protein recognition and enzymatic catalysis. The research of the last years is directed at the identification of the structural bases of the decoding of genetic information. The current area of focus is the specific recognition of aminoacyl-tRNA synthetases (aaRSs) for their cognate amino acid and tRNA, mechanisms of catalysis and editing. Using biochemical methods, site-directed mutagenesis and X-ray crystallography, work carried out on different prokaryotic (including important pathogenic bacteria Enterococcus faecalis, Mycobacterium tuberculosis and Streptococcus pneumoniae), eukaryotic and archaeal systems.

In collaboration with Dr. S. Cusack (the European Molecular Biological Laboratory) the dimensional structures of several aaRSs and their complexes with various combinations of substrata, including the tRNA complexes, are being studied. The synthesis of specific products by aaRSs has been shown to be accompanied by the conformational changes both in the active centre of enzyme and beyond. The data obtained allowed to understand the mechanism of amino acids activation and the molecular mechanism of the recognition of homologous tRNA and their aminoacylation by these enzymes.

The best progress has been made on the seryl-, tyrosyl- and leucyl- tRNA synthetases from Thermus thermophilus, which in prokaryotes can recognise tRNA with a long variable arm. The determination of a complex of SerRs and tRNA Ser provided the first information on the structure of a tRNA with a long variable arm and elucidated the details of how enzyme interacts with tRNA. As a result of solving the structure of TyrRS for the first time an unusual for these enzymes type recognition of tRNA has been demonstrated. Tyrosyl-tRNA synthetase belongs to the first structural class, but its type of recognition is specific for the class 2 aaRSs, where tRNA interacts with an enzyme from the side of a long variable arm. Finally, after the structure of a complex of the leucyl-tRNA synthetase with tRNALeu was determined, a full picture of the interaction of the synthetases with tRNA, which have a long variable arm, has been revealed. The distinctions, revealed in the tertiary structures of tRNASer, tRNATyr and tRNALeu, using the methods of X-ray structure analysis and chemical modification, allow to understand the importance of their role in the identification and discrimination by homologous aaRSs.

The aim of one my project is studying of the molecular mechanisms of editing during aminoacyl-tRNA synthesis for two aminoacyl-tRNA synthetases from two different classes: leucyl- (a class I) and prolyl-tRNA synthetases (a class II).

The differences between human and prokaryotic synthetases are using for development of novel classes of antibiotics against Enterococcus faecalis and Mycobacterium tuberculosis.

Number of publications: 186.

Telephone: +380 44 5265589. Telephone home: +380 44 5692106. Fax: +380 44 5260759. E-mail: mtukalo@imbg.org.ua.

Selected publications :

  1. Fujinada, M., Berthet-Colominas, C., Yaremchuk, A.D., Tukalo, M.A. and Cusack S. Refined crystal structure of the seryl-tRNA synthetase from Thermus thermophilus at 2.5 Е resolution / J . Mol.Biol. (1993) 234, 222-233.
  2. Biou, V., Yaremchuk, A., Tukalo, M., Cusack, S. The crystal structure of a complex between seryl-tRNA synthetase and tRNASer from Thermus thermophilus at 2.9 Е resolution. / Science (1994) 263. 1404-1410.
  3. Cusack, S., Yaremchuk, A., Krikliviy, I. and Tukalo, M. tRNApro anticodon recognition by Thermus thermophilus prolyl-tRNA synthetase./ Structure (1998) 6, 101-108
  4. Egorova, S.P., Yaremchuk, A.D., Kriklivyi, I.A. and Tukalo, M. A. Comparative analysis of interaction sites of Thermus thermophilus and Escherichia coli tRNATyr with homologous aminoacyl-tRNA synthetases by means of chemical modification and nuclease hydrolysis. / Bioorg . Khim. (1998) 24, 593-600.
  5. Kovalenko, O.P., Petrushenko, Z.M., Kriklivyi, I.A., Yaremchuk, A.D. and Tukalo, M.A. A comparative study of phosphate reactivities in tRNASer and tRNALeu from Thermus thermophilus. / Bioorg. Khim. (1999) 25, 768-773
  6. Cusack, S., Yaremchuk, A. and Tukalo, M. The 2Е crystal structure of leucyl-tRNA synthetase and its complex with a leucyl-adenylate analogue / EMBO J. (2000) 19, 2351-2361.
  7. Yaremchuk, A., Cusack, S. and Tukalo, M. The crystal structure of a eukaryote/archaeon-like prolyl-tRNA synthetase and its complex with tRNAPro(CGG). / EMBO J. (2000) -19, 4745-4758
  8. Yaremchuk, A., Tukalo, M., Grotli, M. and Cusack, S. A succession of substrate induced conformational changes ensures the amino acid specificity of Thermus thermophilus prolyl-tRNA synthetase: comparison with histidyl-tRNA synthetase./ J. Mol Biol. (2001) 309, 989-1002
  9. Yaremchuk, A., Kriklivyi, I., Tukalo, M. and Cusack, S. Class I tyrosyl-tRNA synthetase has a class II mode of cognate tRNA recognition. / EMBO J. (2002) 15, 3829-3840.
  10. Lincecum, T.L, Tukalo, M., Yaremchuk, A., Mursinna, R.S., Williams, A.M., Sproat, B.S., Van Den Eynde, W., Link, A., Van Calenbergh ,S,, Grotli, M., Martinis, S.A., and Cusack, S. Structural and Mechanistic Basis of Pre- and Posttransfer Editing by Leucyl-tRNA Synthetase. / Molecular Cell. (2003) 11, 951-963.
  11. Kobayashi, T., Nureki, O., Ishitani, R., Yaremchuk, A., Tukalo, M., Cusack, S., Sakamoto, K. and Yokoyama, S. Structural basis for orthogonal tRNA specificities of tyrosyl-tRNA synthetases for genetic code expansion. / Nature Struct. Biol. (2003) 10, 425-432