Oligomerization as a strategy for cold adaptation: Structure and dynamics of the GH1 beta-glucosidase from Exiguobacterium antarcticum B7

Autor(es)

Zanphorlin, Leticia Maria ^[1] ; de Giuseppe, Priscila Oliveira ^[2] ; Honorato, Rodrigo Vargas ^[2] ; Costa Tonoli, Celisa Caldana ^[2] ; Fattori, Juliana ^[2] ; Crespim, Elaine ^[1] ; Lopes de Oliveira, Paulo Sergio ^[2] ; Ruller, Roberto ^[1] ; Murakami, Mario Tyago ^[2]

Afiliação do(s) autor(es)

^[1] Brazilian Bioethanol Sci & Technol Lab, Sao Paulo - Brazil

^[2] Natl Ctr Res Energy & Mat, Brazilian Biosci Natl Lab, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: SCIENTIFIC REPORTS; v. 6, MAR 31 2016.
• Citações Web of Science: 20

Resumo

Psychrophilic enzymes evolved from a plethora of structural scaffolds via multiple molecular pathways. Elucidating their adaptive strategies is instrumental to understand how life can thrive in cold ecosystems and to tailor enzymes for biotechnological applications at low temperatures. In this work, we used X-ray crystallography, in solution studies and molecular dynamics simulations to reveal the structural basis for cold adaptation of the GH1 beta-glucosidase from Exiguobacterium antarcticum B7. We discovered that the selective pressure of low temperatures favored mutations that redesigned the protein surface, reduced the number of salt bridges, exposed more hydrophobic regions to the solvent and gave rise to a tetrameric arrangement not found in mesophilic and thermophilic homologues. As a result, some solvent-exposed regions became more flexible in the cold-adapted tetramer, likely contributing to enhance enzymatic activity at cold environments. The tetramer stabilizes the native conformation of the enzyme, leading to a 10-fold higher activity compared to the disassembled monomers. According to phylogenetic analysis, diverse adaptive strategies to cold environments emerged in the GH1 family, being tetramerization an alternative, not a rule. These findings reveal a novel strategy for enzyme cold adaptation and provide a framework for the semi-rational engineering of beta-glucosidases aiming at cold industrial processes. (AU)

• Processo FAPESP: 13/13309-0 - Estudos do comportamento funcional e estrutural de enzimas evolutivamente especializadas na degradação de biomassa vegetal com potenciais aplicações biotecnológicas
• Beneficiário: Mário Tyago Murakami
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 14/07135-1 - EMU concedido no processo 2013/13309-0 - aquisição do sistema de eletroforese capilar com detector de fluorescência - Beckman Coulter
• Beneficiário: Mário Tyago Murakami
• Modalidade de apoio: Auxílio à Pesquisa - Programa Equipamentos Multiusuários