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A simple strategy has been developed to construct high-ordered protein nanotubes using electrostatic interactions and "zero-length" crosslinking induced by small molecular ethylenediamine. Furthermore, utilizing covalent crosslinking, we constructed stable nanoenzymes with multi-glutathione peroxidase (GPx) active centers on the surface of the nanotubes, which were anticipated to be ideal functional bionanomaterials.

A Ca(2+) -responsive artificial selenoenzyme was constructed by computational design and engineering of recoverin with the active center of glutathione peroxidase (GPx). By combining the recognition capacity for the glutathione (GSH) substrate and the steric orientation of the catalytic selenium moiety, the engineered selenium-containing recoverin exhibits high GPx activity for the catalyzed reduction of H2 O2 by glutathione (GSH). Moreover, the engineered selenoenzyme can be switched on/off by Ca(2+) -induced allosterism of the protein recoverin. This artificial selenoenzyme also displays excellent antioxidant ability when it was evaluated using a mitochondrial oxidative damage model, showing great potential for controlled catalysis in biomedical applications., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Abstract D‐Amino acid oxidase (DAAO) specifically catalyzes the oxidative deamination of neutral and polar D‐amino acids and finally yields byproducts of hydrogen peroxide. Our previous work demonstrated that the spinal astroglial DAAO/hydrogen peroxide (H2O2) pathway was involved in the process of pain and morphine antinociceptive tolerance. This study aimed to report mouse strain specificity of DAAO inhibitors on antinociception and explore its possible mechanism. DAAO inhibitors benzoic acid, CBIO, and SUN significantly inhibited formalin‐induced tonic pain in Balb/c and Swiss mice, but had no antinociceptive effect in C57 mice. In contrast, morphine and gabapentin inhibited formalin‐induced tonic pain by the same degrees among Swiss, Balb/c and C57 mice. Therefore, mouse strain difference in antinociceptive effects was DAAO inhibitors specific. In addition, intrathecal injection of D‐serine greatly increased spinal H2O2 levels by 80.0% and 56.9% in Swiss and Balb/c mice respectively, but reduced spinal H2O2 levels by 29.0% in C57 mice. However, there was no remarkable difference in spinal DAAO activities among Swiss, Balb/c and C57 mice. The spinal expression of glutathione (GSH) and glutathione peroxidase (GPx) activity in C57 mice were significantly higher than Swiss and Balb/c mice. Furthermore, the specific GPx inhibitor D‐penicillamine distinctly restored SUN antinociception in C57 mice. Our results reported that DAAO inhibitors produced antinociception in a strain‐dependent manner in mice and the strain specificity might be associated with the difference in spinal GSH and GPx activity.

A Ca2+-responsive artificial selenoenzyme was constructed by computational design and engineering of recoverin with the active center of glutathione peroxidase (GPx). By combining the recognition capacity for the glutathione (GSH) substrate and the steric orientation of the catalytic selenium moiety, the engineered selenium-containing recoverin exhibits high GPx activity for the catalyzed reduction of H2O2 by glutathione (GSH). Moreover, the engineered selenoenzyme can be switched on/off by Ca2+-induced allosterism of the protein recoverin. This artificial selenoenzyme also displays excellent antioxidant ability when it was evaluated using a mitochondrial oxidative damage model, showing great potential for controlled catalysis in biomedical applications. [ABSTRACT FROM AUTHOR]