6F4C

Nicotiana benthamiana alpha-galactosidase

Summary for 6F4C

• Entry DOI: 10.2210/pdb6f4c/pdb
• Descriptor: alpha-galactosidase (2 entities in total)
• Functional Keywords: alpha-galactosidase nicotiana benthamiana, hydrolase
• Biological source: Nicotiana benthamiana
• Total number of polymer chains: 1
• Total formula weight: 39927.25

Authors

Kytidou, K.,Aerts, J.M.F.G.,Pannu, N.S. (deposition date: 2017-11-29, release date: 2018-04-25, Last modification date: 2024-11-13)

Primary citation

Kytidou, K.,Beekwilder, J.,Artola, M.,van Meel, E.,Wilbers, R.H.P.,Moolenaar, G.F.,Goosen, N.,Ferraz, M.J.,Katzy, R.,Voskamp, P.,Florea, B.I.,Hokke, C.H.,Overkleeft, H.S.,Schots, A.,Bosch, D.,Pannu, N.,Aerts, J.M.F.G.
Nicotiana benthamianaalpha-galactosidase A1.1 can functionally complement human alpha-galactosidase A deficiency associated with Fabry disease.
J. Biol. Chem., 293:10042-10058, 2018

PubMed Abstract: α-Galactosidases (EC 3.2.1.22) are retaining glycosidases that cleave terminal α-linked galactose residues from glycoconjugate substrates. α-Galactosidases take part in the turnover of cell wall-associated galactomannans in plants and in the lysosomal degradation of glycosphingolipids in animals. Deficiency of human α-galactosidase A (α-Gal A) causes Fabry disease (FD), a heritable, X-linked lysosomal storage disorder, characterized by accumulation of globotriaosylceramide (Gb3) and globotriaosylsphingosine (lyso-Gb3). Current management of FD involves enzyme-replacement therapy (ERT). An activity-based probe (ABP) covalently labeling the catalytic nucleophile of α-Gal A has been previously designed to study α-galactosidases for use in FD therapy. Here, we report that this ABP labels proteins in leaf extracts, enabling the identification and biochemical characterization of an α-galactosidase we name here A1.1 (gene accession ID GJZM-1660). The transiently overexpressed and purified enzyme was a monomer lacking -glycans and was active toward 4-methylumbelliferyl-α-d-galactopyranoside substrate ( = 0.17 mm) over a broad pH range. A1.1 structural analysis by X-ray crystallography revealed marked similarities with human α-Gal A, even including A1.1's ability to hydrolyze Gb3 and lyso-Gb3, which are not endogenous in plants. Of note, A1.1 uptake into FD fibroblasts reduced the elevated lyso-Gb3 levels in these cells, consistent with A1.1 delivery to lysosomes as revealed by confocal microscopy. The ease of production and the features of A1.1, such as stability over a broad pH range, combined with its capacity to degrade glycosphingolipid substrates, warrant further examination of its value as a potential therapeutic agent for ERT-based FD management.

PubMed: 29674318
DOI: 10.1074/jbc.RA118.001774

Experimental method

X-RAY DIFFRACTION (2.8 Å)