title: Cloning of two cellulase genes from endophytic Paenibacillus polymyxa GS01 and comparison with cel 44C-man 26A.
abstract: Endophytic bacteria are acknowledged as a new source of genes, proteins and other biochemical compounds, which are often used in biochemical processes. In this study, Paenibacillus polymyxa GS01 was isolated from the interior of the roots of Korean cultivars of ginseng (Panax ginseng C. A. Meyer). Two cellulase genes, cel 5A and cel 5B, were cloned from GS01, and encode 334 aa and 573 aa proteins, respectively. Cel5A and Cel5B each contain a glycosyl hydrolase family 5 (GH5) catalytic domain. The molecular mass of Cel5A and Cel5B were estimated to be 33 kDa and 61 kDa, respectively, by CMC-SDS-PAGE. When purified from Escherichia coli Cel5A and Cel5B both displayed cellulase activity with pH optima of 7.0 and 6.0, respectively and shared a temperature optimum of 50 degrees C. Neither enzyme had detectable xylanase, lichenase, or mannase activity, in contrast to the multifunctional Cel44C-Man26A enzyme of P. polymyxa which displays cellulase, xylanase, lichenase and mannanase activities. However, Cel5A and Cel5B exhibited higher specific cellulase activity than Cel44C-Man26A (120% and 140%, respectively). Cel5A and Cel5B mutants with alanine substitutions at a conserved glutamic acid in the GH5 domain (Glu 179 of Cel5A and Glu184 of Cel5B) lacked cellulase activity, suggesting that this residue is important for GH5 domain function.
authors.affiliation: Division of Applied Life Science, Gyeongsang National University, Chinju, Korea.
authors.forename: Kye Man
authors.initials: KM
authors.lastname: Cho
authors.forename: Sun Joo
authors.initials: SJ
authors.lastname: Hong
authors.forename: Renukarahya K
authors.initials: RK
authors.lastname: Math
authors.forename: Shah Md Asraful
authors.initials: SM
authors.lastname: Islam
authors.forename: Jong Ok
authors.initials: JO
authors.lastname: Kim
authors.forename: Young Han
authors.initials: YH
authors.lastname: Lee
authors.forename: Hoon
authors.initials: H
authors.lastname: Kim
authors.forename: Han Dae
authors.initials: HD
authors.lastname: Yun