Xanthomonas campestris expansin-like X domain is a structurally disordered beta-sheet macromolecule capable of synergistically enhancing enzymatic efficiency of cellulose hydrolysis

Author(s)

Tomazini Junior, Atilio ^[1] ; Dolce, Luciano Graciani ^[1] ; de Oliveira Neto, Mario ^[2] ; Polikarpov, Igor ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Fis Sao Carlos, Dept Fis & Ciencia Interdisciplinar, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ Estadual Paulista, Inst Biociencias, BR-18618970 Botucatu, SP - Brazil

• Document type: Journal article
• Source: Biotechnology Letters; v. 37, n. 12, p. 2419-2426, DEC 2015.
• Web of Science Citations: 4

Abstract

Objectives To biochemically characterize an expansin-like X protein domain from Xanthomonas campestris (XcEXLX1) and to study its synergy with cellulases in cellulose depolymerization. Results The protein was purified using a combination of ion exchange and size exclusion chromatography rendering about 30 mg pure protein/l culture medium. Circular dichroism spectroscopy and small-angle X-ray scattering studies of XcEXLX1 reveal that it is a strongly disordered beta-sheet protein. Its low resolution envelope fits nicely the crystallographic structure of the homologous protein EXLX1 from Bacillus subtillis. Furthermore, we demonstrate that XcEXLX1 shows a synergistic, pH-dependent effect when combined with a commercial enzymatic preparation (Accellerase 1500), enhancing its hydrolytic activity on a cellulosic substrate. The strongest effect was observed in acid pHs with an increase in sugar release of up to 36 %. Conclusion The synergistic effect arising from the action of the expansin-like protein was considerable in the presence of significantly larger amounts of the commercial enzymatic cocktail then previously observed (0.35 FPU of Accellerase 1500/g substrate). (AU)

• FAPESP's process: 08/56255-9 - Structure and function of enzymes and auxiliary proteins from Trichoderma, active in cell-wall hydrolysis
• Grantee: Igor Polikarpov
• Support type: Program for Research on Bioenergy (BIOEN) - Thematic Grants
• FAPESP's process: 10/52362-5 - Targeted analysis of microbial lignocellulolytic secretomes: a new approach to enzyme discovery
• Grantee: Igor Polikarpov
• Support type: Regular Research Grants
• FAPESP's process: 07/08706-9 - Molecular and Structural Studies of Cellulitic Complex Enzymes of Fungi Trichoderma harzianum with Potencial of Enzymatic Transformation of Biomass
• Grantee: Viviane Isabel Serpa
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 09/05349-6 - Expression and purification of cellobiohydrolase I from the filamentous fungus Trichoderma harzianum
• Grantee: Bruno Luan Soares Paula de Mello
• Support type: Scholarships in Brazil - Scientific Initiation