A Novel Carbohydrate-binding Module from Sugar Cane Soil Metagenome Featuring Unique Structural and Carbohydrate Affinity Properties

Author(s):Show less -

Campos, Bruna Medeia ; Liberato, Marcelo Vizona ; Alvarez, Thabata Maria ; Zanphorlin, Leticia Maria ; Ematsu, Gabriela Cristina ; Barud, Hernane ; Polikarpov, Igor ; Ruller, Roberto ; Gilbert, Harry J. ; de Mattos Zeri, Ana Carolina ; Squina, Fabio Marcio

• Document type: Journal article
• Source: Journal of Biological Chemistry; v. 291, n. 45, p. 23734-23743, NOV 4 2016.
• Web of Science Citations: 5

Abstract

Carbohydrate-binding modules (CBMs) are appended to glycoside hydrolases and can contribute to the degradation of complex recalcitrant substrates such as the plant cell wall. For application in bioethanol production, novel enzymes with high catalytic activity against recalcitrant lignocellulosic material are being explored and developed. In this work, we report the functional and structural study of CBM\_E1, which was discovered through a metagenomics approach and is the founding member of a novel CBM family, CBM81. CBM\_E1, which is linked to an endoglucanase, displayed affinity for mixed linked 1,3-1,4-glucans, xyloglucan, Avicel, and cellooligosaccharides. The crystal structure of CBM\_E1 in complex with cellopentaose displayed a canonical -sandwich fold comprising two -sheets. The planar ligand binding site, observed in a parallel orientation with the -strands, is a typical feature of type A CBMs, although the expected affinity for bacterial crystalline cellulose was not detected. Conversely, the binding to soluble glucans was enthalpically driven, which is typical of type B modules. These unique properties of CBM\_E1 are at the interface between type A and type B CBMs. (AU)

• FAPESP's process: 13/06336-0 - Study of the Molecular Basis of Carbohydrate Binding Modules (CBMs) from Metagenomic Screenings
• Grantee: Bruna Medéia de Campos
• Support type: Scholarships in Brazil - Post-Doctorate
• FAPESP's process: 14/04105-4 - Structural and functional characterization of new cellulases, focusing in the relation between catalytic domains and CBMs
• Grantee: Marcelo Vizoná Liberato
• Support type: Scholarships in Brazil - Post-Doctorate
• 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
• FAPESP's process: 10/11469-1 - Library generation for biomass-conversion enzymes from soil metagenome
• Grantee: Thabata Maria Alvarez
• Support type: Scholarships in Brazil - Doctorate (Direct)