An evolutionary and structure-based docking model for glucocerebrosidase–saposin C and glucocerebrosidase–substrate interactions—Relevance for Gaucher disease

Authors

  • Sílvia Atrian,

    Corresponding author
    1. Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, 08028 Barcelona, Spain
    2. Institut de Biomedicina de la Universitat de Barcelona (IBUB), 08028 Barcelona, Spain
    • Departament de Genètica, Facultat de Biología, Universitat de Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain
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    • Sílvia Atrian and Eduardo López-Viñas contributed equally to this work.

  • Eduardo López-Viñas,

    1. Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Cantoblanco, 28049 Madrid, Spain
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    • Sílvia Atrian and Eduardo López-Viñas contributed equally to this work.

  • Paulino Gómez-Puertas,

    1. Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Cantoblanco, 28049 Madrid, Spain
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  • Amparo Chabás,

    1. Institut de Bioquímica Clínica, Hospital Clinic, Corporació Sanitària Clínic, 08028 Barcelona, Spain
    2. CIBERER, Instituto de Salud Carlos III, Barcelona, Spain
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  • Lluïsa Vilageliu,

    1. Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, 08028 Barcelona, Spain
    2. Institut de Biomedicina de la Universitat de Barcelona (IBUB), 08028 Barcelona, Spain
    3. CIBERER, Instituto de Salud Carlos III, Barcelona, Spain
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    • Lluïsa Vilageliu and Daniel Grinberg are the co-last authors.

  • Daniel Grinberg

    1. Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, 08028 Barcelona, Spain
    2. Institut de Biomedicina de la Universitat de Barcelona (IBUB), 08028 Barcelona, Spain
    3. CIBERER, Instituto de Salud Carlos III, Barcelona, Spain
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    • Lluïsa Vilageliu and Daniel Grinberg are the co-last authors.


Abstract

Gaucher disease, the most prevalent lysosomal storage disorder, is principally caused by malfunction of the lysosomal enzyme glucocerebrosidase (GBA), a 497-amino acid membrane glycoprotein that catalyzes the hydrolysis of glucosylceramide to ceramide and glucose in the presence of an essential 84-residue activator peptide named saposin C (SapC). Knowledge of the GBA structure, a typical (β/α)8 TIM barrel, explains the effect of few mutations, directly affecting or located near the catalytic site. To identify new regions crucial for proper GBA functionality, we analyzed the interactions of the enzyme with a second (substrate) and a third (cofactor) partner. We build 3D docking models of the GBA–SapC and the GBA–ceramide interactions, by means of methodologies that integrate both evolutive and structural information. The GBA–SapC docking model confirm the implication of three spatially closed regions of the GBA surface (TIM barrel-helix 6 and helix 7, and the Ig-like domain) in binding the SapC molecule. This model provides new basis to understand the pathogenicity of several mutations, such as the prevalent Leu444Pro, and the additive effect of Glu326Lys in the double mutant Glu326Lys-Leu444Pro. Overall, 39 positions in which amino acid changes are known to cause Gaucher disease were localized in the GBA regions identified in this work. Our model is discussed in relation to the phenotype (pathogenic effect) of these mutations, as well as to the enzymatic activity of the recombinant proteins when available. Both data fully correlates with the proposed model, which will provide a new tool to better understand Gaucher disease and to design new therapy strategies. Proteins 2008. © 2007 Wiley-Liss, Inc.

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