Schweins R

References (2)

Title : Pressure-induced molten globule state of human acetylcholinesterase: structural and dynamical changes monitored by neutron scattering - Marion_2015_Phys.Chem.Chem.Phys_17_3157
Author(s) : Marion J , Trovaslet M , Martinez N , Masson P , Schweins R , Nachon F , Trapp M , Peters J
Ref : Phys Chem Chem Phys , 17 :3157 , 2015
Abstract : We used small-angle neutron scattering (SANS) to study the effects of high hydrostatic pressure on the structure of human acetylcholinesterase (hAChE). At atmospheric pressure, our SANS results obtained on D11 at ILL (Grenoble, France) give a radius of gyration close to that calculated for a mixture of monomers, dimers and tetramers of the enzyme, suggesting a good agreement between hAChE crystal structure and its conformation in solution. Applying high pressure to the sample we found a global compression of about 11% of the enzyme up to a pressure of 900 bar and then again an extension up to 2.1 kbar indicating unfolding of the tertiary structure due to a molten globule (MG) state. On the other hand, we studied the influence of pressure up to 6 kbar on the dynamics of this enzyme, on the backscattering spectrometer IN13 at ILL. For the first time, we used elastic incoherent neutron scattering (EINS) to probe the differences between hAChE in its folded state (N), its high-pressure induced MG state and its unfolded state (U). Especially around the MG state at 1750 bar we found a significant increase in the dynamics, indicating a partial unfolding. A four-step-model is suggested to describe the changes in the protein.
ESTHER : Marion_2015_Phys.Chem.Chem.Phys_17_3157
PubMedSearch : Marion_2015_Phys.Chem.Chem.Phys_17_3157
PubMedID: 25515378

Title : Enzymatic activity of lipase-nanoparticle conjugates and the digestion of lipid liquid crystalline assemblies - Brennan_2010_Langmuir_26_13590
Author(s) : Brennan JL , Kanaras AG , Nativo P , Tshikhudo TR , Rees C , Fernandez LC , Dirvianskyte N , Razumas V , Skjot M , Svendsen A , Jorgensen CI , Schweins R , Zackrisson M , Nylander T , Brust M , Barauskas J
Ref : Langmuir , 26 :13590 , 2010
Abstract : Variants of lipase were attached to gold nanoparticles (NPs) and their enzymatic activity was studied. The two bioengineered lipase variants have been prepared with biotin groups attached to different residues on the protein outer surface. The biotinylation was evidenced by denaturing polyacrylamide gel electrophoresis and quantified by the ([2-(4'-hydroxyazobenzene)]benzoic acid spectrophotometric test. NPs of 14 +/- 1 nm diameter coated with thiolated-polyethylene glycol ligands containing controlled proportions of biotin moieties have been prepared and characterized by transmission electron microscopy, UV-vis spectroscopy, small angle neutron scattering, and elemental analysis. These biotin-functionalized NPs were conjugated to lipase using streptavidin as a linker molecule. Enzyme activity assays on the lipase-nanoparticle conjugates show that the lipase loading and activity of the NPs can be controlled by varying the percentage of biotin groups in the particle protecting coat. The lipase-NP conjugates prepared using one variant display higher activity than those prepared using the other variant, demonstrating orientation-dependent enzyme activity. Cryogenic transmission electron microscopy was used to visualize the enzymatic activity of lipase-NP on well-defined lipid substrates. It was found that lipase-coated NPs are able to digest the substrates in a different manner in comparison to the free lipase.
ESTHER : Brennan_2010_Langmuir_26_13590
PubMedSearch : Brennan_2010_Langmuir_26_13590
PubMedID: 20695608