Synthesis of uniformly deuterated<i>n</i>-dodecyl-<i>β</i>-<scp>d</scp>-maltoside (<i>d</i><sub>39</sub>-DDM) for solubilization of membrane proteins in TROSY NMR experiments
作者:Kazumi Hiruma-Shimizu、Arnout P. Kalverda、Peter J. F. Henderson、Steve W. Homans、Simon G. Patching
DOI:10.1002/jlcr.3249
日期:2014.12
This work reports the first synthesis of uniformly deuterated n-dodecyl-β-d-maltoside (d39-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 d39-DDM for solubilizing large α-helical membrane proteins in samples for [15N–1H]TROSY (transverse relaxation-optimized spectroscopy) NMR experiments to achieve the highest sensitivity and best resolved spectra possible. Our synthesis of d39-DDM used d7-d-glucose and d25-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 α-configuration, were coupled together with an α(1 → 4) glycosidic bond to give maltose, which was then coupled with n-dodecanol by its substitution of a C1 bromine in the α-configuration to give DDM. 1H NMR spectra were used to confirm a high level of deuteration in the synthesized d39-DDM and to demonstrate its use in eliminating interfering signals from TROSY NMR spectra of a 52-kDa sugar transport protein solubilized in DDM.
A mechanistic study of the non-oxidative decarboxylation catalyzed by the radical S-adenosyl-<scp>l</scp>-methionine enzyme BlsE involved in blasticidin S biosynthesis
Decarboxylation is a fundamentally important reaction in biology and involves highly diverse mechanisms. Here we report a mechanistic study of the non-oxidative decarboxylation catalyzed by BlsE, a radical S-adenosyl-L-methionine (SAM) enzyme involved in blasticidin S biosynthesis. Through a series of biochemical analysis with isotopically labeled reagents, we show that the BlsE-catalyzed reaction