Identification of two inactive forms of the central sulfur cycle protein SoxYZ of Paracoccus pantotrophus.
The central protein of the sulfur-oxidizing enzyme system of Paracoccus pantotrophus, SoxYZ, reacts with three different Sox proteins. Its active site Cys110(Y) is on the carboxy-terminus of the SoxY subunit. SoxYZ "as isolated" consisted mainly of the catalytically inactive SoxY-Y(Z)(2) heterotetramer linked by a Cys110(Y)-Cys110(Y) interprotein disulfide. Sulfide activated SoxYZ "as isolated" 456-fold, reduced the disulfide, and yielded an active SoxYZ heterodimer. The reductant tris(2-carboxyethyl)phosphine (TCEP) inactivated SoxYZ. This form was not re-activated by sulfide, which identified it as a different inactive form. In analytical gel filtration, the elution of "TCEP-treated" SoxYZ was retarded compared to active SoxYZ, indicating a conformational change. The possible enzymes involved in the re-activation of each inactive form of SoxYZ are discussed.
Quentmeier
Armin
A
Lehrstuhl Technische Mikrobiologie, Fakultät Bio- und Chemieingenieurwesen, Technische Universität Dortmund, Emil-Figge-Strasse 66, D-44221 Dortmund, Germany.
Li
Lin
L
Friedrich
Cornelius G
CG
D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000302:isolation & purification; D002384:Catalysis; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification; D008958:Models, Molecular; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000302:isolation & purification; D042084:Paracoccus pantotrophus / Q000201:enzymology*; D010720:Phosphines / Q000494:pharmacology; D021122:Protein Subunits / Q000737:chemistry / Q000302:isolation & purification
D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D050862:Oxidoreductases Acting on Sulfur Group Donors; D010720:Phosphines; D021122:Protein Subunits; C080938:tris(2-carboxyethyl)phosphine; C413329:SoxZ protein, Paracoccus pantotrophus