title: Crystallization and preliminary crystallographic studies of a novel noncatalytic carbohydrate-binding module from the Ruminococcus flavefaciens cellulosome.
abstract: Microbial degradation of the plant cell wall is a fundamental biological process with considerable industrial importance. Hydrolysis of recalcitrant polysaccharides is orchestrated by a large repertoire of carbohydrate-active enzymes that display a modular architecture in which a catalytic domain is connected via linker sequences to one or more noncatalytic carbohydrate-binding modules (CBMs). CBMs direct the appended catalytic modules to their target substrates, thus potentiating catalysis. The genome of the most abundant ruminal cellulolytic bacterium, Ruminococcus flavefaciens strain FD-1, provides an opportunity to discover novel cellulosomal proteins involved in plant cell-wall deconstruction. It encodes a modular protein comprising a glycoside hydrolase family 9 catalytic module (GH9) linked to two unclassified tandemly repeated CBMs (termed CBM-Rf6A and CBM-Rf6B) and a C-terminal dockerin. The novel CBM-Rf6A from this protein has been crystallized and data were processed for the native and a selenomethionine derivative to 1.75 and 1.5 Å resolution, respectively. The crystals belonged to orthorhombic and cubic space groups, respectively. The structure was solved by a single-wavelength anomalous dispersion experiment using the CCP4 program suite and SHELXC/D/E.
authors.affiliation: CIISA, Faculdade de Medicina Veterinaria, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisbon, Portugal.
authors.forename: Immacolata
authors.initials: I
authors.lastname: Venditto
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Guwahati, Assam, India.
authors.forename: Arun
authors.initials: A
authors.lastname: Goyal
authors.affiliation: Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, 91192 Gif-sur-Yvette, France.
authors.forename: Andrew
authors.initials: A
authors.lastname: Thompson
authors.affiliation: CIISA, Faculdade de Medicina Veterinaria, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisbon, Portugal.
authors.forename: Luis M A
authors.initials: LM
authors.lastname: Ferreira
authors.affiliation: CIISA, Faculdade de Medicina Veterinaria, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisbon, Portugal.
authors.forename: Carlos M G A
authors.initials: CM
authors.lastname: Fontes
authors.affiliation: CIISA, Faculdade de Medicina Veterinaria, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisbon, Portugal.
authors.forename: Shabir
authors.initials: S
authors.lastname: Najmudin
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D001665:Binding Sites; D044603:Cellulosomes / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D045857:Ruminococcus
chemical_list: D001426:Bacterial Proteins
keywords: Cel9A; Ruminococcus flavefaciens; carbohydrate-active enzymes; carbohydrate-binding module; glycoside hydrolase family 9