XXII. BIOCHEMICKÝ ZJAZD - Jesseniova lekárska fakulta

Posters
79.
THIOrEDOXIN SYSTEM IN StrEPTOMYCES
Michaela Koháryová and Marta Kollárová
Department of Biochemistry, Faculty of Natural Sciences, Comenius University,
Mlynská dolina CH-1, 842 15 Bratislava, Slovak Republic
Thiol-disulphide bond balance is generally under control of Trx system and/or GSH/GSHR
system in bacteria. Both systems are the main regulators of redox homeostasis, which
can modulate biological activity of many proteins and also participate in protection
against oxidative stress. S. coelicolor A3(2) (like other Streptomycetes) is a suitable model
organism for studying Trx system, because lacks GSH/Grx system (Newton et al., 1996).
In the most prokaryotic and eukaryotic organisms are multiple functions accomplished
by single thioredoxin. The complete genome sequence of S. coelicolor A3(2) (Bentley et
al., 2000) revealed several possible thioredoxin genes: three genes for thioredoxin, two
for putative thioredoxins, one for thioredoxin reductase and two for putative thioredoxin.
Their high sequence similarity can predicted similar physiological functions. All genes
encode proteins with putative oxidoreductase activities, however their biological roles
are not determined yet. It seems, that S. coelicolor has a very complex redox system, what
can be responsible for multicellular development of Streptomyces. We prepared E. coli
strains with overproduced thioredoxins (A, A2, A3) and also thioredoxin reductase TrxB.
We purified the proteins and performed their functional analysis. After first screening
we obtained TrxB protein crystals.
Acknowledgements: This work was supported by project “BIOMAKRO1 ITMS:26240120003”,
“BIOMAKRO2 ITMS:26240120027”, thanks to operating program Research and progression
financed by Europe fund of regional development and also thanks to VEGA grant 1/03/09.
202 XXII. Biochemistry Congress, Martin