DE MIGUEL Natalia
Structural and functional diversity in the family of small heat shock proteins from the parasite Toxoplasma gondii
DE MIGUEL, N.; BRAUN, N.; BEPPERLING, A.; KRIEHUBER, T.; KASTERNMULLER, A.; BUCHNER, J.; ANGEL, S.; HASLBECK, M.
BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH
ELSEVIER SCIENCE BV
Año: 2009 vol. 1793 p. 1738 - 1748
Small heat shock proteins (sHsps) are ubiquitous molecular chaperones which prevent the nonspecificaggregation of non-native proteins. Five potential sHsps exist in the parasite Toxoplasma gondii. They arelocated in different intracellular compartments including mitochondria and are differentially expressedduring the parasite´s life cycle. Here, we analyzed the structural and functional properties of all five proteins.Interestingly, this first in vitro characterization of sHsps from protists showed that all T. gondii sHsps exhibitthe characteristic properties of sHsps such as oligomeric structure and chaperone activity. However,differences in their quaternary structure and in their specific chaperone properties exist. On the structurallevel, the T. gondii sHsps can be divided in small (1218 subunits) and large (2432 subunits) oligomers.Furthermore, they differ in their interaction with non-native proteins. While some bind substrates tightly,others interact more transiently. The chaperone activity of the three more mono-disperse T. gondii sHsps isregulated by temperature with a decrease in temperature leading to the activation of chaperone activity,suggesting an adaption to specific steps of the parasite´s life cycle.