Analysis of molecular and structural causes of metabolic diversity mediated by prenylating enzymes
WOLFGANG BRANDT
LUDGER A. WESSJOHANN
Leibniz Institute of Plant Biochemistry
Weinberg 3
D-06120 Halle/S.
Wolfgang.Brandt@ipb-halle.de
Ludger.Wessjohann@ipb-halle.de
http://www.ipb-halle.de/de/forschung/natur-und-wirkstoffchemie/
Based
on protein homology models, our results concerning site directed mutagenesis
of the active sites residues of hydroxybenzoate oligoprenyltransferase
(ubiA) and of terpene cyclases will be presented and discussed.
More general aspects of the evolution of metabolic diversity of prenylating
enzymes have been and will be investigated by molecular modelling and
bioinformatic studies. As one starting point in this context, all diphosphate
binding sites in proteins were analysed and classified based on the SCOP
database using Perl and the SYBYL programming language. It appeared that
terpene cyclases and short chain isopentenyl diphosphate synthases (IPPSs)
are in close relationship, whereas the long chain IPPSs form an independent
group. Furthermore, the isopentenyl diphosphate DELTA isomerases were
classified together with non-prenylating enzymes. This may indicate an
important hint at the evolutionary origin for the entire class of these
enzymes. These analyses will be continued by more detailed inspections
of the active sites of prenylating enzymes (including new 3d-structures,
which will be provided soon by Prof. Heide, Univ. Tübingen) and distantly
related enzymes.
Furthermore, aromatic prenyltransferases will be isolated from higher
fungi, sequenced and if possible prepared for X-ray crystallographic analysis
or homology modelling. These expected new sequences and structures will
extend the still low number of sequences and resolved 3d-structures of
aromatic prenyltransferases. Together with the extensive bioinformatic
analysis it should offer more insight into the evolution of this special
class of prenylating enzymes.
Close cooperations with a multitude of partners within the priority program
will be continued. These include homology modelling of proteins accompanied
by ligand screening, docking, and advanced quantum mechanical calculations
to investigate catalytic mechanisms. Results obtained so far (1-3) will
also be presented and briefly discussed.
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