Structural and Functional Studies on Human Oxygenases Involved in Metabolism and Disease

The first members of the 2-oxoglutarate (2OG) dependent oxygenase family to be identified were prolyl and lysyl hydroxylases involved in collagen biosynthesis. Subsequently, 2OG oxygenases have been shown to catalyze oxidation reactions in most living organisms, ranging from bacteria and viruses to humans. In plants and microorganisms 2OG oxygenases catalyze many reactions employing small molecule substrates, notably involved in fatty acid metabolism and biosynthesis pathways leading to medicinally important antibiotics (antibiotic biosynthesis). One plant 2OG oxygenase, gibberellin C-20 oxidase, is the target of a commercially used herbicide and the activity of α-amino-α-cyclopropane-carboxylic acid oxidase (ACCO, the ethylene forming enzyme), an enzyme closely related to the 2OG oxygenases, is genetically regulated to control fruit ripening. 2OG oxygenases have also been the subject of study due to their involvement in genetic diseases, e.g. Ehlers–Danlos syndrome (procollagen lysyl hydroxylase) and ischemia related diseases.

There are estimated to be 60-80 human 2OG oxgenases; we aim to define roles for these enzymes at levels ranging the biochemical, i.e. what substrates they work, to the physiological. We are particularly interested in members of the family that are linked to disease, or can be targeted for the treatment of disease. Following the discovery of a role for the HIF hydroxylases in signalling, we, and others, have identified roles for 2OG oxygenases in histone and nucleic acid modification. In some cases we have linked enzyme activity, or impaired activity, to physiology, notably in the case of fat mass and obesity protein (FTO), which is a nucleic acid demethylase, and PHF8, a histone demethylase, mutations of which are linked to cleft lip/palate and mental retardation.

Major current foci for the group include the identification of selective inhibitors for histone demethylases (in collaboration with the Structural Genomics Consortium, SGC) and understanding the function in determining their substrate selectivity.

Techniques involved in this interdisciplinary research include proteomics, X-ray crystallography, biological mass spectrometry, molecular biology, kinetics and organic synthesis/medicinal chemistry.