Characterization of a Hexameric Exo-Acting GH51 alpha-l-Arabinofuranosidase from the Mesophilic Bacillus subtilis

Author(s):Show less -

Hoffmam, Zaira B. ^{[1, 2]} ; Oliveira, Leandro C. ^{[2, 3]} ; Cota, Junio ^{[2, 1]} ; Alvarez, Thabata M. ^{[2, 1]} ; Diogo, Jos A. ^{[1, 2]} ; Neto, Mario de Oliveira ^[4] ; Citadini, Ana Paula S. ^[2] ; Leite, Vitor B. P. ^[3] ; Squina, Fabio M. ^{[2, 1]} ; Murakami, Mario T. ^{[1, 5]} ; Ruller, Roberto ^{[1, 2]}

Affiliation

^[1] Univ Estadual Campinas UNICAMP, Campinas, SP - Brazil

^[2] Ctr Nacl Pesquisa Energia & Mat, Lab Nacl Ciencia & Tecnol Bioetanol, BR-13083970 Campinas, SP - Brazil

^[3] Univ Estadual Paulista IBILCE UNESP, Inst Biociencias Letras & Ciencias Exatas, Dept Fis, Sao Jose Do Rio Preto, SP - Brazil

^[4] UNESP Botucatu, Inst Biociencias, Dept Fis & Biofis, Botucatu, SP - Brazil

^[5] Lab Nacl Biociencias LNBio CNPEM, Campinas, SP - Brazil

• Document type: Journal article
• Source: MOLECULAR BIOTECHNOLOGY; v. 55, n. 3, p. 260-267, NOV 2013.
• Web of Science Citations: 6

Abstract

alpha-l-Arabinofuranosidases (alpha-l-Abfases, EC 3.2.1.55) display a broad specificity against distinct glycosyl moieties in branched hemicellulose and recent studies have demonstrated their synergistic use with cellulases and xylanases for biotechnological processes involving plant biomass degradation. In this study, we examined the structural organization of the arabinofuranosidase (GH51 family) from the mesophilic Bacillus subtilis (AbfA) and its implications on function and stability. The recombinant AbfA showed to be active over a broad temperature range with the maximum activity between 35 and 50 A degrees C, which is desirable for industrial applications. Functional studies demonstrated that AbfA preferentially cleaves debranched or linear arabinan and is an exo-acting enzyme producing arabinose from arabinoheptaose. The enzyme has a canonical circular dichroism spectrum of alpha/beta proteins and exhibits a hexameric quaternary structure in solution, as expected for GH51 members. Thermal denaturation experiments indicated a melting temperature of 53.5 A degrees C, which is in agreement with the temperature-activity curves. The mechanisms associated with the unfolding process were investigated through molecular dynamics simulations evidencing an important contribution of the quaternary arrangement in the stabilization of the beta-sandwich accessory domain and other regions involved in the formation of the catalytic interface of hexameric Abfases belonging to GH51 family. (AU)

• FAPESP's process: 11/17658-3 - Computational studies on protein folding and applications in the study of enzymes involved in bioethanol production
• Grantee: Vitor Barbanti Pereira Leite
• Support type: Regular Research Grants
• FAPESP's process: 10/51890-8 - SMOLBnet 2.0: Structural studies of transcription factors involved in the regulation of hydrolytic enzyme genes and swollenin from Aspergillus niger and A. fumigatus
• Grantee: Mário Tyago Murakami
• Support type: Regular Research Grants
• FAPESP's process: 11/13242-7 - Studies of enzymatic mechanisms for the improvement of bio-fuel production
• Grantee: Leandro Cristante de Oliveira
• Support type: Scholarships in Brazil - Post-Doctorate
• FAPESP's process: 11/14200-6 - Functional studies of microbial hemicellulases with potential biotechnological application in biorefinery of hemicellulosic biomass
• Grantee: Zaira Bruna Hoffmam
• Support type: Scholarships in Brazil - Master
• FAPESP's process: 08/58037-9 - Library generation for biomass-conversion enzymes from soil metagenome
• Grantee: Fábio Márcio Squina
• Support type: Program for Research on Bioenergy (BIOEN) - Young Investigators Grants