2H NMR evidence for dynamic disorder in human skin induced by the penetration enhancer azone
摘要:
Penetration enhancers mediate trans-dermal drug delivery. The penetration enhancer dodecyl-azacycloheptanone (Azone(R)) was characterized in situ with H-2 NMR on human stratum corneum treated with either uniformly deuterated Azone(R) or penetration enhancer with only the entire chain deuterated, in both cases in propylene glycol. The H-2 NMR spectrum at ambient temperature constitutes a single narrow line only 180 Hz wide. This contrasts with the complex lineshapes 1-25 kHz wide commonly observed for methylene deuterons of lipids in a bilayer gel phase, Hence there is no evidence for differences in orientational behaviour between different deuterons at ambient temperature. The narrow line translates into a low overall order parameter S-CD < 0.0008, for all deuterons, revealing rapid motion of the entire enhancer with correlation times tau(c) much less than 6 x 10(-6) s, in all possible directions. At temperatures of about 150 K a H-2 NMR pattern characteristic for a random isotropic powder was observed on samples of stacked stratum corneum sheets at different orientations with respect to the magnetic field. This provides strong evidence for random isotropic freezing of the Azone(R) molecules upon cooling. The H-2 NMR data suggest than incubation with Azone(R) in propylene glycol provokes dynamic structural disorder of the intercellular lamellar lipid structure throughout the stratum corneum and possibly even the creation of fluid domains involving the intercellular lipids, which may be essential for the penetration enhancing effect.
2H NMR evidence for dynamic disorder in human skin induced by the penetration enhancer azone
摘要:
Penetration enhancers mediate trans-dermal drug delivery. The penetration enhancer dodecyl-azacycloheptanone (Azone(R)) was characterized in situ with H-2 NMR on human stratum corneum treated with either uniformly deuterated Azone(R) or penetration enhancer with only the entire chain deuterated, in both cases in propylene glycol. The H-2 NMR spectrum at ambient temperature constitutes a single narrow line only 180 Hz wide. This contrasts with the complex lineshapes 1-25 kHz wide commonly observed for methylene deuterons of lipids in a bilayer gel phase, Hence there is no evidence for differences in orientational behaviour between different deuterons at ambient temperature. The narrow line translates into a low overall order parameter S-CD < 0.0008, for all deuterons, revealing rapid motion of the entire enhancer with correlation times tau(c) much less than 6 x 10(-6) s, in all possible directions. At temperatures of about 150 K a H-2 NMR pattern characteristic for a random isotropic powder was observed on samples of stacked stratum corneum sheets at different orientations with respect to the magnetic field. This provides strong evidence for random isotropic freezing of the Azone(R) molecules upon cooling. The H-2 NMR data suggest than incubation with Azone(R) in propylene glycol provokes dynamic structural disorder of the intercellular lamellar lipid structure throughout the stratum corneum and possibly even the creation of fluid domains involving the intercellular lipids, which may be essential for the penetration enhancing effect.
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.
Invisible detergents for structure determination of membrane proteins by small‐angle neutron scattering
作者:Søren Roi Midtgaard、Tamim A. Darwish、Martin Cramer Pedersen、Pie Huda、Andreas Haahr Larsen、Grethe Vestergaard Jensen、Søren Andreas Røssell Kynde、Nicholas Skar‐Gislinge、Agnieszka Janina Zygadlo Nielsen、Claus Olesen、Mickael Blaise、Jerzy Józef Dorosz、Thor Seneca Thorsen、Raminta Venskutonytė、Christian Krintel、Jesper V. Møller、Henrich Frielinghaus、Elliot Paul Gilbert、Anne Martel、Jette Sandholm Kastrup、Poul Erik Jensen、Poul Nissen、Lise Arleth
DOI:10.1111/febs.14345
日期:2018.1
A novel and generally applicable method for determining structures of membrane proteins in solution via small-angleneutronscattering (SANS) is presented. Common detergents for solubilizing membrane proteins were synthesized in isotope-substituted versions for utilizing the intrinsic neutronscattering length difference between hydrogen and deuterium. Individual hydrogen/deuterium levels of the detergent