Functions of the proteins of the sulfur-oxidizing enzyme system of Paracoccus pantotrophus
Zusammenfassung der Projektergebnisse
The results of a joint project with Prof. Dr. Axel Scheidig, Kiel are reported. In the final period attempts failed to isolate in preparative scale specific substrate-loaded SoxYZ species from a population of differently loaded active and inactive SoxYZ species. The preparative isolation was a prerequisite to identify partial reactions of the cycle of the Sox multi enzyme system and protein-protein interactions. Therefore, we aimed at deducing the specific function from structural properties of the active sites of the proteins. The collaborative research also with other partners to analyze structural and spectroscopic features were encouraging successful. The crystal structure was resolved of sulfane dehydrogenase SoxCD, thioredoxin SoxS and flavoprotein SoxF. EPR and ENDOR spectroscopy confirmed specific substrate access and binding of SoxCD. Electrochemistry differentiated the properties of SoxS and SoxW. We have further described the kinetics of the Sox multi-enzyme system which is unprecedented in enzyme kinetics as four soluble proteins convert one substrate to one product without release of an intermediate. Moreover, in collaboration the functionality of various Sox proteins of the phototroph Allochromatium vinosum was shown by substituting the respective proteins of Paracoccus pantotrophus to reconstitute the Sox enzyme system.
Projektbezogene Publikationen (Auswahl)
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(2008). Sulfur oxidation in Prokaryotes. In: Encyclopedia of Life Sciences. John Wiley & Sons, Ltd: Chichester
Dahl, Christiane; Friedrich, Cornelius & Kletzin, Arnulf
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(2009). Interaction between Sox proteins of two physiologically distinct bacteria and a new protein involved in thiosulfate oxidation. FEBS Lett. 583. 1281-1286
Welte C, Hafner S, Krätzer C, Quentmeier A, Friedrich CG, Dahl C
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(2011). A combined fluorescence spectroscopic and electrochemical approach for the study of thioredoxins. Biochemistry 50, 17-24
Voicescu M, Rother D, Bardischewsky F, Friedrich CG, Hellwig P
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(2011). Spectroscopic characterization oft he molybdenum cofactor oft he sulfane dehydrogenase SoxCD from Paracoccus pantotrophus. Inorg. Chem. 50, 409-411
Drew SC, Reijerse E, Quentmeier A, Rother D, Friedrich CG, Lubitz W
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(2011). Structural basis for the oxidation of protein-bound sulfur by the sulfur cycle molybdohemo-enzyme sulfane dehydrogenase SoxCD. J. Biol. Chem. 286, 8349-8360
Zander U, Faust A, Klink BU, de Sanctis D, Panjikar S, Quentmeier A, Bardischewsky F, Friedrich CG, Scheidig A
