We welcome Dr Wyatt W. Yue, who will attend the APBDRF Scientific Advisory Board Meeting for the first time this December. He leads a group at the Structural Genomics Consortium, University of Oxford, where his primary interest is structural biology of inherited metabolic diseases and development of small molecule therapy.
His planned participation is in the following areas:
- Recombinant protein production of GBE1 (he has established a system that yields low milligram quantities for biochemical and structural work)
- Looking into the thermal stability of GBE1 protein comparing WT and mutants (e.g. Y329S)
- Characterizing small molecule hits (from various screening efforts) using in vitro and structural methods to evaluate binding and specificity.
‘Structural studies of human GBE1 and relevance to APBD’
PI, Metabolic & Rare Diseases
Structural Genomics Consortium
University of Oxford
The Structural Genomics Consortium (SGC) is a public-private partnership that conducts pre-competitive research to facilitate the discovery of new medicines. Our primary objectives are to produce three-dimensional structures of human proteins with medical relevance, as well as target-specific chemical tool compounds, and release them into the public domain with no restriction on use. Under this mandate, the Metabolic & Rare Diseases group at the SGC combines structural and biochemical approaches to study proteins that are linked with inborn errors of metabolism (IEM), a heterogeneous set of rare genetic diseases associated with enzyme dysfunction and deficiency. With a repertoire to date of > 50 crystals structures and further 120 recombinant human proteins linked with IEM, we have established a protein-centric collaborative platform in partnership with clinicians, geneticists, and drug developers.
One of our research focuses is the eukaryotic glycogen biosynthetic machinery, where inherited defects are known to cause a subset of glycogen storage disorders (GSD). In mammals, glycogen biosynthesis involves three proteins, namely the priming enzyme glycogenin (GYG1/2), the elongation enzyme glycogen synthase (GYS1/2), and the branching enzyme (GBE1). In particular, mutations on the GBE1 gene lead to an extremely heterogeneous GSD type IV, in terms of onset age, natural history and disease severity, but the clinical hallmark is the accumulation of an insoluble, poorly-branched form of glycogen (polyglucosan body) in affected tissues. A clinical allelic variant of GSD type IV is the late-onset neurological disorder, adult polyglucosan body disease (APBD), where a prevalent missense mutation p.Y329S (c.1076A>C) is found.
We have an on-going interest in establishing a structural understanding of the catalytic mechanism and disease mutations of human GBE1, since existing information at the protein level is only available from bacteria and plant homologues. Our initial attempts to over-express human GBE1 in E. coli, nevertheless, have not yielded any soluble recombinant protein. This difficulty was circumvented by the use of baculovirus-infected insect cell expression, coupled with an extensive survey on the N- and C-terminal boundaries that are amenable to soluble protein formation. With this approach, we have obtained recombinant GBE1 both in the wild-type and mutant forms, to facilitate structural and ligand-binding studies. Our long-term goal is to establish a molecular basis for the disease-causing mutations (e.g. p.Y329S) and to develop ‘pharmacological chaperones’ that could provide a novel therapeutic perspective for the debilitating disorder.