RoxA is isolated with O2 stably bound to the active site heme iron. Activation and cleavage of O2 require binding of polyisoprene, and the substrate needs to use hydrophobic access channels to reach the deeply buried active site of RoxA. Both residues H312 and Y462 are ideally positioned to form hydrogen bonds that arrest the substrate chain, so that the bond connecting the third and fourth monomer is in close proximity to the O2 ligand at heme 1. After oxidative cleavage, the resulting 2-oxo-4,8-dimethyl-trideca-4,8-diene-1-al product dissociates, and RoxA slides along the isoprene chain until the terminus is again arrested by hydrogen bonds
enzyme degrades both natural rubber latex and chemosynthetic poly(cis-1,4-isoprene) in vitro by oxidative cleavage of the double bonds of poly(cis-1,4-isoprene). Enzymatic cleavage of rubber by the purified protein is strictly dependent on the presence of oxygen
presence of two c-type heme centers that show two distinct alpha-bands at 549 and 553 nm in the dithionite-reduced state. One heme shows a midpoint potential of –65 mV. One of the two haems is reduced by NADH (549 nm alpha-band)
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
to 1.8 A resolution. The enzyme shows an unusually low degree of secondary structure. RoxA incorporates both oxygen atoms of its cosubstrate dioxygen into the rubber cleavage product 12-oxo-4,8-dimethyl-trideca-4,8-diene-1-al
development of an in vitro enzyme assay for oxidative rubber degradation based on high-performance liquid chromatography analysis and spectroscopic detection of product carbonyl functions after derivatization with dinitrophenylhydrazone
optimization of a transformation system via electroporation, and a conjugation system for expression of RoxA in Xanthomonas sp. About 6 mg purified RoxA are obtained from 1 l of cell-free culture fluid