THE CONFORMATION OF THE TRISACCHARIDE AND TETRASACCHARIDE PRODUCED INTHE HYDROLYSIS OF BARLEY GLUCAN WITH THE ENZYME ENDO-1,3-1,4-BETA-GLUCAN 4-GLUCANOHYDROLASE FROM BACILLUS-LICHENIFORMIS

The solution conformation of the tri- and tetrasaccharide obtained by enzymatic degradation of glucan has been analysed using molecular mech anics and dynamics calculations and nuclear magnetic resonance data. T he overall shape of both compounds is fairly similar and may be descri bed by an equilibrium formed by conformers included in the low energy regions for both glycosidic linkages. The interglycosidic torsion angl es for these conformers are Phi(H)=15+/-45 degrees and Psi(H)=-20+/-30 degrees for both beta(1->4) linkages and Phi(H)=40+/-15 degrees and P si(H)=-20+/-35 degrees for the corresponding beta(1->3)-linked moiety.