TY  - JOUR
A1  - Wellert, Stefan
A1  - Tiersch, Brigitte
A1  - Koetz, Joachim
A1  - Richardt, Andre
A1  - Lapp, Alain
A1  - Holderer, Olaf
A1  - Gaeb, Juergen
A1  - Blum, Marc-Michael
A1  - Schulreich, Christoph
A1  - Stehle, Ralf
A1  - Hellweg, Thomas
T1  - The DFPase from Loligo vulgaris in sugar surfactant-based bicontinuous microemulsions  structure, dynamics, and enzyme activity
JF  - European biophysics journal : with biophysics letters ; an international journal of biophysics
N2  - The enzyme diisopropyl fluorophosphatase (DFPase) from the squid Loligo vulgaris is of great interest because of its ability to catalyze the hydrolysis of highly toxic organophosphates. In this work, the enzyme structure in solution (native state) was studied by use of different scattering methods. The results are compared with those from hydrodynamic model calculations based on the DFPase crystal structure. Bicontinuous microemulsions made of sugar surfactants are discussed as host systems for the DFPase. The microemulsion remains stable in the presence of the enzyme, which is shown by means of scattering experiments. Moreover, activity assays reveal that the DFPase still has high activity in this complex reaction medium. To complement the scattering experiments cryo-SEM was also employed to study the microemulsion structure.
KW  - Dynamic light scattering
KW  - Neutron spin echo
KW  - Microemulsion
KW  - Enzyme catalysis
KW  - SANS
KW  - Protein structure
Y1  - 2011
U6  - https://doi.org/10.1007/s00249-011-0689-0
SN  - 0175-7571
VL  - 40
IS  - 6
SP  - 761
EP  - 774
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Spricigo, Roberto
A1  - Leimkühler, Silke
A1  - Gorton, Lo
A1  - Scheller, Frieder W.
A1  - Wollenberger, Ursula
T1  - The Electrically Wired Molybdenum Domain of Human Sulfite Oxidase is Bioelectrocatalytically Active
JF  - European journal of inorganic chemistry : a journal of ChemPubSoc Europe
N2  - We report electron transfer between the catalytic molybdenum cofactor (Moco) domain of human sulfite oxidase (hSO) and electrodes through a poly(vinylpyridine)-bound [osmium(N,N'-methyl-2,2'-biimidazole)(3)](2+/3+) complex as the electron-transfer mediator. The biocatalyst was immobilized in this low-potential redox polymer on a carbon electrode. Upon the addition of sulfite to the immobilized separate Moco domain, the generation of a significant catalytic current demonstrated that the catalytic center is effectively wired and active. The bioelectrocatalytic current of the wired separate catalytic domain reached 25% of the signal of the wired full molybdoheme enzyme hSO, in which the heme b(5) is involved in the electron-transfer pathway. This is the first report on a catalytically active wired molybdenum cofactor domain. The formal potential of this electrochemical mediator is between the potentials of the two cofactors of hSO, and as hSO can occupy several conformations in the polymer matrix, it is imaginable that electron transfer from the catalytic site to the electrode through the osmium center occurs for the hSO molecules in which the Moco domain is sufficiently accessible. The observation of catalytic oxidation currents at low potentials is favorable for applications in bioelectronic devices.
KW  - Metalloenzymes
KW  - Enzyme catalysis
KW  - Immobilization
KW  - Osmium
Y1  - 2015
U6  - https://doi.org/10.1002/ejic.201500034
SN  - 1434-1948
SN  - 1099-0682
IS  - 21
SP  - 3526
EP  - 3531
PB  - Wiley-VCH
CY  - Weinheim
ER  -