Structure of the Bacillus agaradherans family 5 endoglucanase at 1.6 Å and its cellobiose complex at 2.0 Å resolution

TY - JOUR

T1 - Structure of the Bacillus agaradherans family 5 endoglucanase at 1.6 Å and its cellobiose complex at 2.0 Å resolution

AU - Davies, Gideon J.

AU - Dauter, Miroslawa

AU - Brzozowski, A. Marek

AU - Bjørnvad, Mads Eskelund

AU - Andersen, Kim V.

AU - Schülein, Martin

PY - 1998/2/17

Y1 - 1998/2/17

N2 - The enzymatic degradation of cellulose, by cellulases, is not only industrially important in the food, paper, and textile industries but also a potentially useful method for the environmentally friendly recycling of municipal waste. An understanding of the structural and mechanistic requirements for the hydrolysis of the β-1,4 glycosidic bonds of cellulose is an essential prerequisite for beneficial engineering of cellulases for these processes. Cellulases have been classified into 13 of the 62 glycoside hydrolase families [Henrissat, B., and Bairoch, A. (1996) Biochem J. 316, 695-696]. The structure of the catalytic core of the family 5 endoglucanase, Cel5A, from the alkalophilic Bacillus agaradherans has been solved by multiple isomorphous replacement at 1.6 Å resolution. Cel5A has the (α/β)8 barrel structure and signature structural features typical of the grouping of glycoside hydrolase families known as clan GH-A, with the catalytic acid/base Glu 139 and nucleophile Glu 228 on barrel strands β4 and β7 as expected. In addition to the native enzyme, the 2.0 Å resolution structure of the cellobiose-bound form of the enzyme has also been determined. Cellobiose binds preferentially in the -2 and -3 subsites of the enzyme. Kinetic studies on the isolated catalytic core domain of Cel5A, using a series of reduced cellodextrins as substrates, suggest approximately five to six binding sites, consistent with the shape and size of the cleft observed by crystallography.

AB - The enzymatic degradation of cellulose, by cellulases, is not only industrially important in the food, paper, and textile industries but also a potentially useful method for the environmentally friendly recycling of municipal waste. An understanding of the structural and mechanistic requirements for the hydrolysis of the β-1,4 glycosidic bonds of cellulose is an essential prerequisite for beneficial engineering of cellulases for these processes. Cellulases have been classified into 13 of the 62 glycoside hydrolase families [Henrissat, B., and Bairoch, A. (1996) Biochem J. 316, 695-696]. The structure of the catalytic core of the family 5 endoglucanase, Cel5A, from the alkalophilic Bacillus agaradherans has been solved by multiple isomorphous replacement at 1.6 Å resolution. Cel5A has the (α/β)8 barrel structure and signature structural features typical of the grouping of glycoside hydrolase families known as clan GH-A, with the catalytic acid/base Glu 139 and nucleophile Glu 228 on barrel strands β4 and β7 as expected. In addition to the native enzyme, the 2.0 Å resolution structure of the cellobiose-bound form of the enzyme has also been determined. Cellobiose binds preferentially in the -2 and -3 subsites of the enzyme. Kinetic studies on the isolated catalytic core domain of Cel5A, using a series of reduced cellodextrins as substrates, suggest approximately five to six binding sites, consistent with the shape and size of the cleft observed by crystallography.

UR - http://www.scopus.com/inward/record.url?scp=0032539533&partnerID=8YFLogxK

U2 - 10.1021/bi972162m

DO - 10.1021/bi972162m

M3 - Article

C2 - 9485319

AN - SCOPUS:0032539533

SN - 0006-2960

VL - 37

SP - 1926

EP - 1932

JO - Biochemistry

JF - Biochemistry

IS - 7

ER -