TY  - JOUR
A1  - Folikumah, Makafui Y.
A1  - Behl, Marc
A1  - Lendlein, Andreas
T1  - Reaction behaviour of peptide-based single thiol-thioesters exchange reaction substrate in the presence of externally added thiols
JF  - MRS communications / a publication of the Materials Research Society
N2  - Identification of patterns in chemical reaction pathways aids in the effective design of molecules for specific applications. Here, we report on model reactions with a water-soluble single thiol-thioester exchange (TTE) reaction substrate, which was designed taking in view biological and medical applications. This substrate consists of the thio-depsipeptide, Ac-Pro-Leu-Gly-SLeu-Leu-Gly-NEtSH (TDP) and does not yield foul-smelling thiol exchange products when compared with aromatic thiol containing single TTE substrates. TDP generates an alpha,omega-dithiol crosslinker in situ in a 'pseudo intramolecular' TTE. Competitive intermolecular TTE of TDP with externally added "basic" thiols increased the crosslinker concentration whilst "acidic" thiols decreased its concentration. TDP could potentially enable in situ bioconjugation and crosslinking applications.
KW  - Biomaterials
KW  - Biomimetic
KW  - Mass spectrometry
KW  - Nuclear magnetic resonance
KW  - (NMR)
Y1  - 2021
U6  - https://doi.org/10.1557/s43579-021-00041-z
SN  - 2159-6859
SN  - 2159-6867
VL  - 11
IS  - 4
SP  - 402
EP  - 410
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Mitreiter, Ivonne
A1  - Oswald, Sascha
A1  - Stallmach, Frank
T1  - Magnetic resonance measurements of iron turn-over in sands
T1  - Magnetresonanz-Messung von Eisenumsatzprozessen in Sanden
BT  - Nicht-invasive Charakterisierung von Reaktionsabläufen
BT  - non-invasive characterization of reaction processes
JF  - Grundwasser : Zeitschrift der Fachsektion Hydrogeologie in der Deutschen Gesellschaft für Geowissenschaften (FH-DGG)
N2  - In this study, Nuclear Magnetic Resonance (NMR), a non-destructive measurement technique, has been applied for investigation of iron turn-over processes. In non-invasive laboratory experiments, iron dissolution and precipitation reactions in saturated natural sands were observed spatially and temporally. These processes play an important role in groundwater with varying redox and pH conditions. Redox reactions turning Fe2+ into Fe3+ and Fe3+ into Fe2+ were detected in aqueous solution by the difference in magnetic relaxation times. Furthermore, the spatial distribution of the iron reduction reaction, the consumption and diffusive transfer to and from the reaction sites, was observed in a 1D set-up with natural sands. The achieved spatial resolution was less than one millimetre while repeating measurements every half an hour. It showed the system changing from diffusion-limited to reaction-limited.
KW  - Nuclear magnetic resonance
KW  - Ferric iron
KW  - Ferrous iron
KW  - Acidification
KW  - Redox reaction
KW  - Reactive transport modelling
Y1  - 2011
U6  - https://doi.org/10.1007/s00767-011-0177-6
SN  - 1430-483X
VL  - 16
IS  - 4
SP  - 269
EP  - 278
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - JOUR
A1  - Sowemimo, Oluwakemi T.
A1  - Knox-Brown, Patrick
A1  - Borcherds, Wade
A1  - Rindfleisch, Tobias
A1  - Thalhammer, Anja
A1  - Daughdrill, Gary W.
T1  - Conserved Glycines Control Disorder and Function in the Cold-Regulated Protein, COR15A
JF  - Biomolecules
N2  - Cold-regulated (COR) 15A is an intrinsically disordered protein (IDP) from Arabidopsis thaliana important for freezing tolerance. During freezing-induced cellular dehydration, COR15A transitions from a disordered to mostly alpha-helical structure. We tested whether mutations that increase the helicity of COR15A also increase its protective function. Conserved glycine residues were identified and mutated to alanine. Nuclear magnetic resonance (NMR) spectroscopy was used to identify residue-specific changes in helicity for wildtype (WT) COR15A and the mutants. Circular dichroism (CD) spectroscopy was used to monitor the coil-helix transition in response to increasing concentrations of trifluoroethanol (TFE) and ethylene glycol. The impact of the COR15A mutants on the stability of model membranes during a freeze-thaw cycle was investigated by fluorescence spectroscopy. The results of these experiments showed the mutants had a higher content of alpha-helical structure and the increased alpha-helicity improved membrane stabilization during freezing. Comparison of the TFE- and ethylene glycol-induced coil-helix transitions support our conclusion that increasing the transient helicity of COR15A in aqueous solution increases its ability to stabilize membranes during freezing. Altogether, our results suggest the conserved glycine residues are important for maintaining the disordered structure of COR15A but are also compatible with the formation of alpha-helical structure during freezing induced dehydration.
KW  - COR15A
KW  - Late embryogenesis abundant
KW  - intrinsically disordered proteins
KW  - Trifluoroethanol
KW  - Nuclear magnetic resonance
Y1  - 2019
U6  - https://doi.org/10.3390/biom9030084
SN  - 2218-273X
VL  - 9
IS  - 3
PB  - MDPI
CY  - Basel
ER  -