Half-Barrels Derived from a (beta/alpha)(8) Barrel beta-Glycosidase Undergo an Activation Process

Autor(es)

Beton, Daniela ^[1] ; Marana, Sandro R. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Quim, Dept Bioquim, BR-01498 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: PLoS One; v. 10, n. 10 OCT 2 2015.
• Citações Web of Science: 2

Resumo

The evolution of (beta/alpha)(8) barrel proteins is currently thought to have involved the fusion of two (beta/alpha)(4) half-barrels, thereby conferring stability on the protein structure. After the formation of a whole (beta/alpha)(8) barrel, this structure could evolve and diverge to form fully active enzymes. Interestingly, we show here that isolated (beta/alpha)(4) half-barrels derived from the N- and C-terminal domains of the beta-glucosidase Sf beta gly (Sf beta gly-N: residues 1 to 265; Sf beta gly-C: residues 266 to 509) undergo an activation process, which renders them catalytically active. The rate constants of the activation process were calculated to be 0.029 and 0.032 h(-1) for Sf beta gly-N and Sf beta gly-C, respectively. Moreover, the Sf beta gly-N and Sf beta gly-C activation processes were simultaneous with modifications in their initial structure, which reduced the exposure of their tryptophan residues. Importantly, this activation was also coincident with an increase in the sizes of Sf beta gly-N and Sf beta gly-C particles. These novel observations suggest that the change in catalytic activity associated with the transition from a half to whole (beta/alpha)(8) barrel might also have driven such an evolutionary process. (AU)

• Processo FAPESP: 08/55914-9 - (bioen/pronex FAPESP) Development of beta-glycosidases designed to improve the efficiency of noncomplexed cellulase systems
• Beneficiário: Sandro Roberto Marana
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOEN - Temático