The impact of O-glycan chemistry on the stability of intrinsically disordered proteins

Autor(es)

Prates, Erica T. ^{[1, 2]} ; Guan, Xiaoyang ^{[3, 4]} ; Li, Yaohao ^{[3, 4]} ; Wang, Xinfeng ^{[3, 4]} ; Chaffey, Patrick K. ^{[3, 4]} ; Skaf, Munir S. ^[2] ; Crowley, Michael F. ^[5] ; Tan, Zhongping ^{[3, 4]} ; Beckham, Gregg T. ^[1]

Afiliação do(s) autor(es)

^[1] Natl Renewable Energy Lab, Natl Bioenergy Ctr, Golden, CO 80403 - USA

^[2] Univ Estadual Campinas, Ctr Computat Engn & Sci, Inst Chem, BR-13084862 Campinas, SP - Brazil

^[3] Univ Colorado, Dept Chem & Biochem, Boulder, CO 80303 - USA

^[4] Univ Colorado, BioFrontiers Inst, Boulder, CO 80303 - USA

^[5] Natl Renewable Energy Lab, Biosci Ctr, Golden, CO 80403 - USA

• Tipo de documento: Artigo Científico
• Fonte: CHEMICAL SCIENCE; v. 9, n. 15, p. 3710-3715, APR 21 2018.
• Citações Web of Science: 6

Resumo

Protein glycosylation is a diverse post-translational modification that serves myriad biological functions. O-linked glycans in particular vary widely in extent and chemistry in eukaryotes, with secreted proteins from fungi and yeast commonly exhibiting O-mannosylation in intrinsically disordered regions of proteins, likely for proteolysis protection, among other functions. However, it is not well understood why mannose is often the preferred glycan, and more generally, if the neighboring protein sequence and glycan have coevolved to protect against proteolysis in glycosylated intrinsically disordered proteins (IDPs). Here, we synthesized variants of a model IDP, specifically a natively O-mannosylated linker from a fungal enzyme, with alpha-O-linked mannose, glucose, and galactose moieties, along with a nonglycosylated linker. Upon exposure to thermolysin, O-mannosylation, by far, provides the highest extent of proteolysis protection. To explain this observation, extensive molecular dynamics simulations were conducted, revealing that the axial configuration of the C2-hydroxyl group (2-OH) of alpha-mannose adjacent to the glycan-peptide bond strongly influences the conformational features of the linker. Specifically, alpha-mannose restricts the torsions of the IDP main chain more than other glycans whose equatorial 2-OH groups exhibit interactions that favor perpendicular glycan-protein backbone orientation. We suggest that IDP stiffening due to O-mannosylation impairs protease action, with contributions from protein-glycan interactions, protein flexibility, and protein stability. Our results further imply that resistance to proteolysis is an important driving force for evolutionary selection of alpha-mannose in eukaryotic IDPs, and more broadly, that glycan motifs for proteolysis protection likely coevolve with the protein sequence to which they attach. (AU)

• Processo FAPESP: 16/04775-5 - Simulações em multi-escala de enzimas e complexos enzimáticos para degradação de biomassa lignocelulósica
• Beneficiário: Érica Teixeira Prates
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Pós-Doutorado
• Processo FAPESP: 13/08293-7 - CECC - Centro de Engenharia e Ciências Computacionais
• Beneficiário: Munir Salomao Skaf
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs