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Struktur und Dynamik Poster: Mi., 14:00–16:30 M-P143
SAXS-studies on structure function relationships of thiamine diphosphatedependent
enzymes
Stephan König 1
1 Institut für Biochemie, Fachbereich Biochemie/Biotechnologie, Martin-Luther-
Universität Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle (Saale)
A dozen of thiamine diphosphate-dependent enzymes have been investigated by means
of small-angle X-ray solution scattering with synchrotron radiation. As a result of this
it became obvious that SAXS is the method of choice to determine the oligomer state
of enzymes in aqueous solutions. Furthermore it was possible to study the influence of
a number of specific ligands, like substrates, activators, inhibitors, cofactors, and pH
on the oligomerisation state and stability of enzymes in solution. Recently, the availability
of corresponding programs allows the calculation of three-dimensional structure
models of the enzymes directly from experimental scattering patterns ab initio without
any further prerequisites. Comparison of these models to crystal structure models
demonstrated the general reliability of these procedures. Furthermore it is possible
to compare both kinds of structure models and to draw conclusions on the spatial
arrangement of enzymes in aqueous solutions. Together with kinetic studies and protein
crystal structure analysis, the SAXS is a powerful method to elucidate structure
function relationships of enzymes.