title: Crystal structure of a putative exo-β-1,3-galactanase from Bifidobacterium bifidum S17.
abstract: Given the current interest in second-generation biofuels, carbohydrate-active enzymes have become the most important tool to overcome the structural recalcitrance of the plant cell wall. While some glycoside hydrolase families have been exhaustively described, others remain poorly characterized, especially with regard to structural information. The family 43 glycoside hydrolases are a diverse group of inverting enzymes; the available structure information on these enzymes is mainly from xylosidases and arabinofuranosidase. Currently, only one structure of an exo-β-1,3-galactanase is available. Here, the production, crystallization and structure determination of a putative exo-β-1,3-galactanase from Bifidobacterium bifidum S17 (BbGal43A) are described. BbGal43A was successfully produced and showed activity towards synthetic galactosides. BbGal43A was subsequently crystallized and data were collected to 1.4 Å resolution. The structure shows a single-domain molecule, differing from known homologues, and crystal contact analysis predicts the formation of a dimer in solution. Further biochemical studies are necessary to elucidate the differences between BbGal43A and its characterized homologues.
authors.affiliation: Departamento de Física em São Carlos, Universidade de São Paulo, Avenida Trabalhador Saocarlense 400, 13560-970 São Carlos-SP, Brazil.
authors.forename: Andre S
authors.initials: AS
authors.lastname: Godoy
authors.affiliation: Departamento de Física em São Carlos, Universidade de São Paulo, Avenida Trabalhador Saocarlense 400, 13560-970 São Carlos-SP, Brazil.
authors.forename: Mariana Z T
authors.initials: MZ
authors.lastname: de Lima
authors.affiliation: Centro de Tecnologia Canavieira, Fazenda Santo Antonio, PO Box 162, 13400-970 Piracicaba-SP, Brazil.
authors.forename: Cesar M
authors.initials: CM
authors.lastname: Camilo
authors.affiliation: Departamento de Física em São Carlos, Universidade de São Paulo, Avenida Trabalhador Saocarlense 400, 13560-970 São Carlos-SP, Brazil.
authors.forename: Igor
authors.initials: I
authors.lastname: Polikarpov
mesh_terms: D000595:Amino Acid Sequence; D000069985:Bifidobacterium bifidum / Q000201:enzymology*; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D004798:Enzymes / Q000737:chemistry / Q000378:metabolism*; D005685:Galactans / Q000378:metabolism*; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
chemical_list: D004798:Enzymes; D005685:Galactans
keywords: Bifidobacterium; GH43; family 43; galactanase; hydrolase