7QQF

Crystal structure of unliganded MYORG

Summary for 7QQF

• Entry DOI: 10.2210/pdb7qqf/pdb
• Related: 7QQG 7QQH
• Descriptor: Myogenesis-regulating glycosidase, alpha-D-mannopyranose-(1-6)-beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ... (9 entities in total)
• Functional Keywords: gh31, glycoside hydrolase, myorg, net37, galactosidase, hydrolase
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 4
• Total formula weight: 297953.30

Authors

Meek, R.W.,Davies, G.J. (deposition date: 2022-01-07, release date: 2022-08-31, Last modification date: 2024-01-31)

Primary citation

Meek, R.W.,Brockerman, J.,Fordwour, O.B.,Zandberg, W.F.,Davies, G.J.,Vocadlo, D.J.
The primary familial brain calcification-associated protein MYORG is an alpha-galactosidase with restricted substrate specificity.
Plos Biol., 20:e3001764-e3001764, 2022

PubMed Abstract: Primary familial brain calcification (PFBC) is characterised by abnormal deposits of calcium phosphate within various regions of the brain that are associated with severe cognitive impairments, psychiatric conditions, and movement disorders. Recent studies in diverse populations have shown a link between mutations in myogenesis-regulating glycosidase (MYORG) and the development of this disease. MYORG is a member of glycoside hydrolase (GH) family 31 (GH31) and, like the other mammalian GH31 enzyme α-glucosidase II, this enzyme is found in the lumen of the endoplasmic reticulum (ER). Though presumed to act as an α-glucosidase due to its localization and sequence relatedness to α-glucosidase II, MYORG has never been shown to exhibit catalytic activity. Here, we show that MYORG is an α-galactosidase and present the high-resolution crystal structure of MYORG in complex with substrate and inhibitor. Using these structures, we map detrimental mutations that are associated with MYORG-associated brain calcification and define how these mutations may drive disease progression through loss of enzymatic activity. Finally, we also detail the thermal stabilisation of MYORG afforded by a clinically approved small molecule ligand, opening the possibility of using pharmacological chaperones to enhance the activity of mutant forms of MYORG.

PubMed: 36129849
DOI: 10.1371/journal.pbio.3001764

Experimental method

X-RAY DIFFRACTION (2.43 Å)