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Crystal structure for UGT (UDP-glycosyltransferase)
in a plant related to Arabidopsis thaliana.
Image � byCutler lab, UC
Riverside. |
Focusing on Arabidopsis thaliana, a weedy
plant in the mustard family, Cutler�s lab discovered a key protein in
the plant that creates drug resistance. Called UGT (UDP-glycosyltransferase),
the protein is a member of a family of proteins that also affect drug
sensitivity in humans.
�Similar biochemical processes are affecting drug sensitivity in both
plants and animals,� said Cutler, who joined UCR�s Department of
Botany and Plant Sciences and the Center for Plant Cell Biology in
January 2007. �These similarities suggest that plants can be useful
for studying problems of human interest like drug responses.�
In their research, Cutler and his research team first screened and
tested thousands of drug-like compounds in the lab as they searched
for new inhibitors of plant growth. In the process, they discovered a
new molecule, called hypostatin, which acts like a drug in inhibiting
plant growth in some Arabidopsis plants.
At the same time, the researchers grew Arabidopsis plants in a
solution containing hypostatin, which allowed the plant cells to take
up hypostatin.
Cutler and his team found that the plants� UGT activates hypostatin by
adding a sugar molecule to it. They also found that in plants that had
a genetically defective UGT, hypostatin did not work properly because
no sugar molecules � necessary for activating hypostatin � were added
to it; in such plants, therefore, growth was not affected.
�This mechanism is very similar to that seen in humans, where altered
drug sensitivity can occur because of defective or atypical
sugar-tagging proteins,� Cutler said.
His lab made the discovery as part of its ongoing research aimed at
identifying and characterizing new bioactive compounds in plants. Next
in their research, Cutler and his colleagues plan to expand their
search for other sugar-activated molecules, like hypostatin.
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