Publications by authors named "Roland P T Chung"

20alpha-hydroxysteroid dehydrogenase (AKR1C1) plays a key role in the metabolism of progesterone and other steroid hormones, thereby regulating their action at the pre-receptor level. AKR1C1 is implicated in neurological and psychiatric conditions such as catamenial epilepsy and depressive disorders. Increased activity of AKR1C1 is associated with termination of pregnancy and the development of breast cancer, endometriosis and endometrial cancer.

View Article and Find Full Text PDF

Mouse 3(17)alpha-hydroxysteroid dehydrogenase (AKR1C21) is a bifunctional enzyme that catalyses the oxidoreduction of the 3- and 17-hydroxy/keto groups of steroid substrates such as oestrogens, androgens and neurosteroids. The structure of the AKR1C21-NADPH binary complex was determined from an orthorhombic crystal belonging to space group P2(1)2(1)2(1) at a resolution of 1.8 A.

View Article and Find Full Text PDF

Dimeric dihydrodiol dehydrogenase (DD) catalyses the nicotinamide adenine dinucleotide phosphate (NADP+)-dependent oxidation of trans-dihydrodiols of aromatic hydrocarbons to their corresponding catechols. This is the first report of the crystal structure of the dimeric enzyme determined at 2.0 A resolution.

View Article and Find Full Text PDF

Structure determination of porcine aldehyde reductase holoenzyme in complex with the potent aldose reductase inhibitor fidarestat was carried out to explain the difference in the potency of the inhibitor for aldose and aldehyde reductases. The hydrogen bonds between the active-site residues Tyr50, His113, and Trp114 and fidarestat are conserved in the two enzymes. In aldose reductase, Leu300 forms a hydrogen bond through its main-chain nitrogen atom with the exocyclic amide group of the inhibitor, which when replaced with a Pro in aldehyde reductase, cannot form a hydrogen bond, thus causing a loss in binding energy.

View Article and Find Full Text PDF

L-Xylulose reductase (XR), an enzyme in the uronate cycle of glucose metabolism, belongs to the short-chain dehydrogenase/reductase (SDR) superfamily. Among the SDR enzymes, XR shows the highest sequence identity (67%) with mouse lung carbonyl reductase (MLCR), but the two enzymes show different substrate specificities. The crystal structure of human XR in complex with reduced nicotinamide adenine dinucleotide phosphate (NADPH) was determined at 1.

View Article and Find Full Text PDF

Human sorbitol dehydrogenase (SDH) was expressed in Escherichia coli BL21 cells and purified using ammonium sulfate precipitation and anion-exchange and dye-affinity chromatography. Purified SDH was crystallized from polyethylene glycol solutions using the hanging-drop vapour-diffusion method. X-ray data were collected to 2.

View Article and Find Full Text PDF

Aldose reductase, a monomeric NADPH-dependent oxidoreductase, catalyzes the reduction of a wide variety of aldehydes and ketones to their corresponding alcohols. The X-ray structure of human aldose reductase holoenzyme in complex with statil was determined at a resolution of 2.1 A.

View Article and Find Full Text PDF
Article Synopsis
  • The study describes the crystallization of human L-xylulose reductase using a hanging-drop vapor-diffusion technique, resulting in high-quality crystals.
  • The obtained crystals can diffract X-rays to a resolution of 2.1 Å and fall into the orthorhombic P222 space group, with specific unit-cell dimensions.
  • This is the first documented case of crystallizing a xylulose reductase that is the same as diacetyl reductase, indicating a significant advancement in understanding this enzyme.
View Article and Find Full Text PDF
Article Synopsis
  • Dihydrodiol dehydrogenase is an enzyme that oxidizes trans-dihydrodiols of aromatic hydrocarbons to catechols and has various forms in mammalian tissues.
  • The dimeric form of this enzyme has a unique structure that suggests it may be part of a new protein family related to prokaryotic enzymes.
  • The monkey kidney version of this enzyme has been crystallized, showing high-resolution diffraction, and its crystals belong to specific hexagonal space groups with defined unit-cell parameters.
View Article and Find Full Text PDF