Search

Glycosidase is an indispensable enzyme in the sugar industry. It is difficult to maintain the stability of natural glycosidase during long-term high-temperature sugar conversion, limiting its application in industrial production. Numerous studies have shown that protein engineering is an important means for enhancing the thermal stability of glycosidase. This article systematically reviews the latest advances in using protein engineering to improve the thermal stability of glycosidase, and dissects the directed evolution, rational design, and semi-rational design strategies used in protein engineering. It also evaluates the effectiveness of these strategies in enhancing the thermal stability of glycosidase and their potential industrial application value, and presents the advantages, limitations and challenges of each strategy. Finally, it suggests that different strategies should be jointly used to improve the thermal stability of glycosidase and gives an outlook on future research directions with a view to promoting the synergistic improvement of the thermal stability and activity of glycosidase.

Bacteria are ideal anticancer agents and carriers due to their unique capabilities that are convenient in genetic manipulation, tumor‐specific targeting, and deep‐tissue penetration. However, the specific molecular mechanisms of bacteria‐mediated cancer therapy (BMCT) have not been clarified. In this study, we found that TLR4 signaling pathway is critical for Salmonella‐mediated tumor targeting, tumor suppression, and liver and spleen protection. TLR4 knockout in mice decreased the levels of cytokines and chemokines, such as S100a8, S100a9, TNF‐α, and IL‐1β, in tumor microenvironments (TMEs) after Salmonella treatment, which inhibited tumor cell death and nutrient release, led to reduced bacterial contents in tumors and attenuated antitumor efficacy in a negative feedback manner. Importantly, we found that S100a8 and S100a9 played a leading role in Salmonella‐mediated cancer therapy (SMCT). The antitumor efficacy was abrogated and liver damage was prominent when blocked with a specific inhibitor. These findings elucidated the mechanism of Salmonella‐mediated tumor targeting, suppression, and host antibacterial defense, providing insights into clinical cancer therapeutics. [ABSTRACT FROM AUTHOR]

G3139, an antisense Bcl-2 phosphorothioate oligodeoxyribonucleotide, induces apoptosis in melanoma and other cancer cells. This apoptosis happens before and in the absence of the downregulation of Bcl-2 and thus seems to be Bcl-2-independent. Binding of G3139 to mitochondria and its ability to close voltage-dependent anion-selective channel (VDAC) have led to the hypothesis that G3139 acts, in part, by interacting with VDAC channels in the mitochondrial outer membrane (21). In this study, we demonstrate that G3139 is able to reduce the mitochondrial outer membrane permeability to ADP by a factor of 6 or 7 with a [K.sub.i] between 0.2 and 0.5 [micro]M. Because VDAC is responsible for this permeability, this result strengthens the aforesaid hypothesis. Other mitochondrial respiration components are not affected by [G3139] up to 1 [micro]M. Higher levels begin to inhibit respiration rates, decrease light scattering and increase uncoupled respiration. These results agree with accumulating evidence that VDAC closure favors cytochrome c release. The speed of this effect (within 10 min) places it early in the apoptotic cascade with cytochrome c release occurring at later times. Other phosphorothioate oligonucleotides are also able to induce VDAC closure, and there is some length dependence. The phosphorothioate linkages are required to induce the reduction of outer membrane permeability. At levels below 1 [micro]M, phosphorothioate oligonucleotides are the first specific tools to restrict mitochondrial outer membrane permeability. respiration; voltage-dependent anion-selective channel; apoptosis; cell death

Mutations in superoxide dismutase 1 (SOD1) cause amyotrophic lateral sclerosis (ALS) in 20% of familial cases (fALS). Mitochondria are one of the targets of mutant SOD1 (mutSOD1) toxicity. We previously demonstrated that at the mitochondria, mutSOD1 forms a toxic complex with Bcl-2, which is then converted into a toxic protein via a structural rearrangement that exposes its toxic BH3 domain (Pedrini et al., 2010). Here we now show that formation of this toxic complex with Bcl-2 is the primary event in mutSOD1-induced mitochondrial dysfunction, inhibiting mitochondrial permeability to ADP and inducing mitochondrial hyperpolarization. In mutSOD1-G93A cells and mice, the newly exposed BH3 domain in Bcl-2 alters the normal interaction between Bcl-2 and VDAC1 thus reducing permeability of the outer mitochondrial membrane. In motor neuronal cells, the mutSOD1/Bcl-2 complex causes mitochondrial hyperpolarization leading to cell loss. Small SOD1-like therapeutic peptides that specifically block formation of the mutSOD1/Bcl-2 complex, recover both aspects of mitochondrial dysfunction: they prevent mitochondrial hyperpolarization and cell loss as well as restore ADP permeability in mitochondria of symptomatic mutSOD1-G93A mice.