Structure of potent quinone reductase 2 (QR2) inhibitor, a blueberry extract, using x-ray crystallography

"Quinone reductase 2 (QR2) is a mammalian cytosolic flavoprotein that catalyzes the two electron reduction of quinone to hydroquinone. Inhibition of this enzyme is thought to be a detoxifying mechanism in that QR2 may transform certain quinone substrates into more highly reactive compounds capable of causing cellular damage. The QR2 active site consists of an FAD which forms the floor of the active site, and Phe126, Phe131, and Ile128 that line the active site pocket forming a large hydrophobic surface area that surrounds Asn161, which is involved in hydrogen bonding to the majority of inhibitors studied to date. X-Ray crystallography has revealed that this unique active site allows the binding of naturally occurring polyphenols such as resveratrol, anthocyanin and quercetin. We are currently studying a variety of extracts from fruits such as blueberries and grapes in search of new QR2 inhibitors. X-ray crystallography of a blueberry extract in complex with QR2 (between 1.2 and 1.5Å) has revealed unique insights into the QR2 active site. The image submitted is the QR2 active site (shown in grey sticks with red and blue balls) in complex with a blueberry extract (shown in yellow sticks). The image was created using PyMol."