STRUCTURE STUDIES OF MACROMOLECULAR SYSTEMS

J. Hašek, J. Dohnálek, T. Skálová, J. Dušková, P.Kolenko

Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovského nám. 2, 16206 Praha 6, Czech Republic

hasek@imc.cas.cz

The lecture summarizes briefly results of our laboratory achieved during the last six years. Most of the structure studies are based on our measurements at the X-ray diffraction beam-lines ID14, ID29 in ESRF. Special attention is devoted to future perspectives and to limits of diffraction techniques in solving problems in their complexity to deliver results useful in medicine or technical practice.

Polymer systems – experimental structure determination and applications

Main obstacle of structure determination of synthetic polymers is high structural variability and disorder resulting from the fact that these systems are never in equilibrium state as a rule. Of course, the exact structure determination is meaningful in the cases when some conformations of the polymer chain are markedly preferred. It is in the case of crystalline or semi-crystalline areas in polymer material and also in all instances where the polymer chain specifically interacts with biological material.

· Polymer structure database maintained by our group /1/

· Diffusion and sorption of polymer molecules in protein crystals

· Experimental determination of interactions between synthetic polymers and proteins /2/

· Use of polymers in protein crystallization

Drug design (case study of HIV protease)

• Inhibition of enzymatic processes – optimization of inhibitors for AIDS treatment (inhibitors of HIV protease mutants) /3,4,5/
• Binding of inhibitor – enthalpy and entropy of inhibited enzyme system /6/
• Delivery of drugs and controlled release (activation) of drugs in the target tissue
• Removal of products

Modulation of catalytic systems

• Modulation of activity of aspartic proteases

o HIV protease mutants /5/

o Self-inhibition of HIV protease by its own product of enzymatic cleavage /7/

• Coordinated motions in macromolecular systems – motion of HIV protease flaps necessary for inhibitor (substrate) entrance
• Modulation of temperature optimum for enzymatic activity (b-galactosidase) /9/
• Diffusion of small molecules in proteins
• 3D design of catalytic systems

Intercellular signaling in immunology – complex systems based on molecular recognition

• Immonuglobulin-like receptors /8/
• Cellular receptors
• Membrane rafting of receptors into clusters of cooperating macromolecules

The project was supported by GA AV A4050811/1998 and MŠMT 1K05008 .

1. Hašek J., Labský J. Polymer Structure Database, ÚMCH AV ČR, 1996.

2. Hašek J. (2006) Z. Kristallogr. S23, 613-618.

3. Dohnálek, J., Hašek, J., Dušková, J., Petroková, H., Hradilek, M., Souček, M., Konvalinka, J., Brynda, J., Sedláček, J., Fábry, M. (2002) J. Med. Chem. 45, 1432-1438.

4. Petroková, H., Skálová, T., Dohnálek, J., Dušková, J., Buchtelová, E., Souček, M., Konvalinka, J., Brynda, J., Fábry, JM., Sedláček, J., Hašek, J. (2004) Eur.J.Biochem. 271, 4451-4461.

5. Dušková, J., Dohnálek, J., Skálová, T., Petroková, H., Vondráčková, E., Hradílek, M., Konvalinka, J., Souček, M., Brynda, J., Fábry, M., Sedláček, J., Hašek, J. (2006) Acta Crystallogr. D62, 489-497.

6. Hašek, J., Skálová, T., Dohnálek, J., Dušková, J., Petroková, H., Vondráčková, E., Zimmerman, K. (2005) Materials Structure 12, 208-210.

7. Buchtelová, E., Hašek, J., Dohnálek, J.,Petroková, H., Dušková, J., Skálová, T., Brynda J., Sedláček J., Hradílek, M., Konvalinka, J., Tykartska E., Jaskolski M., Olivi L. (2001) Materials Structure 8, 31-32.

8. Kolenko, P., Dohnálek, J., Štouračová, R., Skálová, T., Tiščenko,G. Dušková, J., Hašek J. (2005). Materials Structure, 12, 146-147.

9. Skálová, T., Dohnálek, J. , Spiwok, V., Lipovová, P., Vondráčková, E., Petroková, H.,Dušková, J., Strnad, H., Králová, B.,Hašek, J. (2005) J. Mol. Biol., 353, 282-284.