MEASUREMENT OF 3-BOND COUPLING-CONSTANTS IN THE OSMOREGULATED PERIPLASMIC GLUCAN OF BURKHOLDERIA-SOLANACEARUM

The cyclic osmoregulated periplasmic glucan produced by Burkholderia s olanacearum contains 13 glucose units, all beta-(1-2) linked except fo r one alpha-(1-6) linkage. We report here the measurement of the (3)J( C1-H2') and (3)J(H1-C2') coupling constants, characterizing the glycos idic linkages, through the use of a C-13/C-12 double half-filtered NOE SY experiment. The values obtained give information about the (Phi Psi ) angles of the different linkages. The results presented form an impo rtant step towards a detailed experimental model of the cyclic glucan, which might allow us to clarify its biological role and establish whe ther the cavity of these molecules is compatible with the capability o f complexing host molecular signals.