Insights into the metagenomic approach : identification and characterization of cellulases involved in bacterial cellulose synthesis

• Main Authors: Berlemont, Renaud, Delsaute, Maud, Galleni, Moreno
• Other Authors: CIP - Centre d'Ingénierie des Protéines - ULiège
• Format: Conference Object
• Language: English
• Published: 2010
• Subjects: cellulose; metagenomic; Life sciences; Biochemistry; biophysics & molecular biology; Sciences du vivant; Biochimie; biophysique & biologie moléculaire; Antarctic; Antarc*
• Online Access: https://orbi.uliege.be/handle/2268/95402

the mining of an Antarctic soil sample by functional metagenomics allowed the isolation of a cold-adapted protein (RBcel1) that hydrolyzes only carboxymethyl cellulose. The new enzyme is related to family 5 of the glycosyl hydrolase (GH5) protein from Pseudomonas stutzeri (Pst_2494) and does not possess a carbohydrate-binding domain. The protein was produced and purified to homogeneity. RBcel1 displayed an endoglucanase activity, producing cellobiose and cellotriose, using carboxymethyl cellulose as a substrate. Moreover, the study of pH and the thermal dependence of the hydrolytic activity shows that RBcel1 was active from pH 6 to pH 9 and remained significantly active when temperature decreased (18% of activity at 10 1C). It is interesting that RBcel1 was able to synthetize non-reticulated cellulose using cellobiose as a substrate. Moreover, by a combination of bioinformatics and enzyme analysis, the physiological relevance of the RBcel1 protein and its mesophilic homologous Pst_2494 protein from P. stutzeri, A1501, was established as the key enzymes involved in the production of cellulose by bacteria. In addition, RBcel1 and Pst_2494 are the two primary enzymes belonging to the GH5 family involved in this process. GeneHunt