Synthesis of uniformly deuterated n-dodecyl-β-D-maltoside (d39-DDM) for solubilization of membrane proteins in TROSY NMR experiments

This work reports the first synthesis of uniformly deuterated n-dodecyl--d-maltoside (d(39)-DDM). DDM is a mild non-ionic detergent often used in the extraction and purification of membrane proteins and for solubilizing them in experimental studies of their structure, dynamics and binding of ligands. We required d(39)-DDM for solubilizing large -helical membrane proteins in samples for [N-15-H-1]TROSY (transverse relaxation-optimized spectroscopy) NMR experiments to achieve the highest sensitivity and best resolved spectra possible. Our synthesis of d(39)-DDM used d(7)-d-glucose and d(25)-n-dodecanol to introduce deuterium labelling into both the maltoside and dodecyl moieties, respectively. Two glucose molecules, one converted to a glycosyl acceptor with a free C4 hydroxyl group and one converted to a glycosyl donor substituted at C1 with a bromine in the -configuration, were coupled together with an (14) glycosidic bond to give maltose, which was then coupled with n-dodecanol by its substitution of a C1 bromine in the -configuration to give DDM. H-1 NMR spectra were used to confirm a high level of deuteration in the synthesized d(39)-DDM and to demonstrate its use in eliminating interfering signals from TROSY NMR spectra of a 52-kDa sugar transport protein solubilized in DDM.