Identificação dos determinantes estruturais de Fe/MnSODs necessários a especificidade por metal.

Abstract

Superoxide dismutases (SODs) are metalloenzymes that convert the superoxide anion in molecular oxygen (O2) and hydrogen peroxide (H2O2). The metal in the catalytic center of such enzymes is directly related to their catalysis mechanisms and tridimensional structures. Evolutionarily, FeSOD and MnSOD may have evolved from a common ancestor, because both proteins have homologous primary sequences and superposable crystallographic structures. However, at the catalytic level, both proteins diverged sufficiently to prevent interchange of their metallic centers, which would generate non-functional enzymes, indicating that these proteins have high metal specificity. The objective of this research project is to identify structural determinants of Fe/MnSODs necessary to metal specificity. We intend to use statistical coupling analysis (SCA) to select amino acid residues for site-directed mutagenesis in TrMnSOD e TbFeSODB2. Mutant genes will be constructed and their proteins expressed, purified and crystallized. The tridimensional structure of such mutants will be solved by X-ray crystallography and their enzymatic activities determined, as well as their electron paramagnetic resonance spectra. We hypothesize that SCA is useful to identify amino acid candidates for site-directed mutagenesis to design new SODs with intermediated Fe/Mn specificity, and even metal specificity interconversion, by studying the evolutionary history of these proteins.

Delivery of superoxide dismutase by TAT and abalone peptides for the protection of skin cells against oxidative stress

“…These results corroborate the data from Chambergo et al 19 . and Fontolan 46 who also obtained TrSOD expression upon induction with IPTG. The expression of superoxide dismutase 1 (SOD1) in fusion with the CPP TAT has also been reported 22,47–50 .…”

“…Bacteria were able to express the proteins TrSOD, TAT-TrSOD-Yfp, and Ab-TrSOD under the used conditions. These results corroborate the data from Chambergo et al 19 and Fontolan 46 who also obtained TrSOD expression upon induction with IPTG. The expression of superoxide dismutase 1 (SOD1) in fusion with the CPP TAT has also been reported.…”