title: Purification and characterization of a molybdenum-pterin-binding protein (Mop) in Clostridium pasteurianum W5.
abstract: A large-scale fractionation scheme purified the major molybdenum(Mo)-binding protein (Mop) from crude extracts of Clostridium pasteurianum, with a 10 and 0.2% yield of Mo and protein, respectively. The apparent molecular weight of the purified molybdoprotein is 5,700, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The protein contains 0.7 mol of Mo per mol of protein with a molecular weight of 5,700. Mop, as isolated, has a peak absorbency at 293 nm. Denaturation and oxidation of the molybdoprotein released multiple pterin like fluorescent compounds. Mop appears to contain a pterin derivative and Mo, but phosphate analysis indicated that the pterin at the very least is not phosphorylated; phosphorylation is required for functional molybdenum cofactor. All treatments used to release the putative Mo-pterin species from Mop failed to yield a molybdopterin that had detectable molybdenum cofactor activity.
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis / Q000302:isolation & purification*; D002352:Carrier Proteins / Q000032:analysis / Q000302:isolation & purification*; D003013:Clostridium / Q000032:analysis*; D008982:Molybdenum / Q000032:analysis / Q000378:metabolism*; D011622:Pterins / Q000032:analysis
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D011622:Pterins; C050771:mopI protein, Clostridium pasteurianum; D008982:Molybdenum