Expression, characterization and synergistic interactions of Myxobacter Sp. AL-1 Cel9 and Cel48 glycosyl hydrolases.
The soil microorganism Myxobacter Sp. AL-1 regulates in a differential manner the production of five extracellular cellulases during its life cycle. The nucleotide sequence of a cel9-cel48 cluster from the genome of this microorganism was recently obtained. Cel48 was expressed in Escherichia coli to generate a His(6)-Cel48 protein and the biochemical properties of the pure protein were determined. Cel48 was more efficient in degrading acid-swollen avicel (ASC) than carboxymethylcellulose (CMC). On the other hand, cel9 was expressed in Bacillus subtilis from an IPTG-inducible promoter. Zymogram analysis showed that after IPTG-induction, Cel9 existed in both the cell fraction and the culture medium of B. subtilis and the secreted protein was purified to homogeneity by FPLC-ionic exchange chromatography. The exocellobiohydrolase Cel48 showed a synergism of 1.68 times with the endocellulase Cel9 during ASC degradation using an 8.1-fold excess of Cel48 over Cel9. Western blot analysis revealed that both proteins were synthesized and secreted to the culture medium of Myxobacter Sp. AL-1. These results show that the cel9-cel48 cluster encodes functional endo- and exo-acting cellulases that allows Myobacter Sp. AL-1 to hydrolyse cellulose.
Ramírez-Ramírez
Norma
N
Instituto de Investigación en Biología Experimental (IIBE), Facultad de Química, Universidad de Guanajuato, P.O. Box 187, Guanajuato, Gto. 36050, Mexico.
Romero-García
Eliel R
ER
Instituto de Investigación en Biología Experimental (IIBE), Facultad de Química, Universidad de Guanajuato, P.O. Box 187, Guanajuato, Gto. 36050, Mexico.
Calderón
Vianney C
VC
Instituto de Investigación en Biología Experimental (IIBE), Facultad de Química, Universidad de Guanajuato, P.O. Box 187, Guanajuato, Gto. 36050, Mexico.
Avitia
Claudia I
CI
Instituto de Investigación en Biología Experimental (IIBE), Facultad de Química, Universidad de Guanajuato, P.O. Box 187, Guanajuato, Gto. 36050, Mexico.
Téllez-Valencia
Alfredo
A
Instituto de Ciencias de la Salud, Universidad Autónoma del Estado de Hidalgo, Abasolo 600, Pachuca, Hgo 42000, Mexico.
Pedraza-Reyes
Mario
M
Instituto de Investigación en Biología Experimental (IIBE), Facultad de Química, Universidad de Guanajuato, P.O. Box 187, Guanajuato, Gto. 36050, Mexico.