A Novel Carbohydrate-binding Module from Sugar Cane Soil Metagenome Featuring Unique Structural and Carbohydrate Affinity Properties.
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 β1,3-β1,4-glucans, xyloglucan, Avicel, and cellooligosaccharides. The crystal structure of CBM_E1 in complex with cellopentaose displayed a canonical β-sandwich fold comprising two β-sheets. The planar ligand binding site, observed in a parallel orientation with the β-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.
From the Laboratório Nacional de Biociências (LNBio).
Bruna Medeia
BM
Campos
the Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), and.
Marcelo Vizona
http://orcid.org/0000-0002-7609-7844
MV
Liberato
the Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), and.
Thabata Maria
TM
Alvarez
the Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), and.
Letícia Maria
LM
Zanphorlin
the Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), and.
Gabriela Cristina
GC
Ematsu
the Centro Universitário de Araraquara-UNIARA, BioPolMat, CEP 14801-340, Araraquara-SP, Brazil.
Hernane
H
Barud
the Instituto de Física de São Carlos, Universidade de São Paulo, CEP 13566-590, São Carlos, São Paulo, Brazil.
Igor
I
Polikarpov
the Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), and.
Roberto
R
Ruller
the Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle-upon-Tyne NE 4HH, United Kingdom, and.
Harry J
HJ
Gilbert
the Laboratório Nacional de Luz Sincrotron (LNLS), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), CEP 13083-970, Campinas, São Paulo, Brazil.
Ana Carolina de Mattos
AC
Zeri
the Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), and fabio.squina@bioetanol.org.br.
Fabio Marcio
FM
Squina
D001419:Bacteria / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002480:Cellulase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism; D018360:Crystallography, X-Ray; D005936:Glucans / Q000378:metabolism; D054892:Metagenome; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D009844:Oligosaccharides / Q000378:metabolism; D011487:Protein Conformation; D031786:Saccharum / Q000382:microbiology*; D012988:Soil Microbiology; D013816:Thermodynamics; D014990:Xylans / Q000378:metabolism
D005936:Glucans; D009844:Oligosaccharides; D014990:Xylans; C019193:maltopentaose; C029353:xyloglucan; D002482:Cellulose; D002480:Cellulase
X-ray crystallography; carbohydrate-binding protein; cellulose; glycoside hydrolase; metagenomics