Rupasinghe, Sanjeewa G. , Schuler, Mary A. .
Modeling of plant P450 monooxygenase structures: a three-dimensional perspective on the evolution of their catalytic activities.
Plant cytochrome P450 monooxygenases represent the largest collection of P450s available for comparative studies as well as pharmacological, agronomic and phytoremediative applications. Current databases list more than 1000 P450 sequences obtained from a small subset of plant species with most from Oryza sativa (rice), Arabidopsis thaliana (mustard), Lycopersicon esculentum (tomato) and Physcomitrella patens (moss). Central to our use of these catalytically competent enzymes is the need to understand their interactions with substrates and their ability to evolve new catalytic activities. Because most characterized P450s are membrane-bound proteins resistant to standard X-ray and NMR structure determinations, for many, homology modeling represents a reliable and relatively rapid alternative method for analyzing structure-function relationships and predicting substrate ranges. Improvements in modeling procedures gained from discrimination of bacterial and mammalian P450 crystal structures have enhanced our structural predictions of catalytic site residues potentially impacting the reactivities of individual plant P450s. Validations of homology modelings with site-directed mutagenesis of plant and insect P450s have begun to provide structural explanations for sequence variants and the evolution of P450 activities within individual subfamilies. Heterologous expressions of full-length Arabidopsis P450s in E. coli systems have allowed us to proceed with the structural characterization of these enzymes using solid state NMR and X-ray crystallographic techniques.
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1 - University of Illinois, Department of Cell and Developmental Biology
2 - University of Illinois, Cell and Developmental Biology, 190 Edward R. Madigan Laboratory (ERML), 1201 W. Gregory Dr., Urbana, Illinois, 61801, United States
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM