Leucine zipper as a bridge for transaminase self-assembly: A fusion enzyme for efficient chiral conversion of d-phenylglycine.

Amino acid transferase is a family of enzymes used to catalyze and separate chiral amino acids. However, due to the low efficiency, by-products and reverse reactions occur in cascade reactions. Therefore, in the research, phenylglycine aminotransferase and aspartate aminotransferase were self-assembled in vitro by leucine zipper. The self-assembled enzyme system with d-phenylglycine and α-ketoglutarate as substrates were used for the chiral transformation reaction. By studying the enzyme combination, kinetic reaction stability and catalytic efficiency, it was found that the self-assembled enzyme showed improved stability and better affinity to the substrate than the control and achieved only ee value of 17.86% for the control at the substrate ratio was 1:2. In contrast, the self-assembled enzyme basically catalyzed the complete conversion of d-Phg to l-Phg, with the ee value as 99%. These results demonstrated the feasibility of the leucine zipper and the conversion of d-phenylglycine to the l-type by fusion enzyme.

Converting Plastic Wastes to Naphtha for Closing the Plastic Loop.

To solve the serious environmental problem and huge resource waste of plastic pollution, we report a tandem catalytic conversion of low-density polyethylene (LDPE) into naphtha, the key feedstock for renewable plastic production. Using ß zeolite and silicalite-1-encapsulated Pt nanoparticles (Pt@S-1), a naphtha yield of 89.5% is obtained with 96.8% selectivity of C5-C9 hydrocarbons at 250 °C. The acid sites crack long-chain LDPE into olefin intermediates, which diffuse within the channels of Pt@S-1 to encounter Pt nanoparticles. The hydrogenation over confined metal matches cracking steps by selectively shipping the olefins with right size, and the rapid diffusion boosts the formation of narrow-distributed alkanes. A conceptual upgrading indicates it is suitable for closing the plastic loop, with a significant energy saving of 15% and 30% reduced greenhouse gas emissions.

Correlation between rs13347 polymorphism of CD44 gene and the risk of occurring breast cancer: A protocol for systematic review and meta-analysis.

BACKGROUND: With the attention paid to the heritability of breast cancer, the search for the genetic susceptibility gene of breast cancer has become a hot spot. At present, a number of studies have explored the relationship between rs13347 polymorphism of cluster of differentiation 44 (CD44) gene and breast cancer, but the research conclusions are inconsistent. Therefore, we will use this meta-analysis to explore the role of this gene polymorphism in breast cancer susceptibility. METHODS: The search time is set from the establishment of the database in March 2021 in this study. The search database include China National Knowledge Infrastructure, Wanfang, VIP Information Chinese Journal Service Platform, and China Biology Medicine disc, PubMed, EMBASE, Web of Science and the Cochrane Library. The subjects are observational studies on the relationship between rs13347 polymorphism of CD44 gene and breast cancer (including case-control study, cross-sectional study and a cohort study). The language is limited to English and Chinese. The data of the included study are extracted and the literature quality is evaluated by two researchers independently. The data are statistically analyzed by Stata 16.0 software. RESULTS: Based on the existing studies, this study will systematically evaluate the relationship between CD44 gene rs13347 polymorphism and breast cancer. CONCLUSION: This study will provide evidence-based medical evidence to clarify the role of CD44 gene polymorphism in breast cancer, and provide help for the early detection and preventive intervention of breast cancer. ETHICS AND DISSEMINATION: Private information from individuals will not be published. This systematic review also does not involve endangering participant rights. Ethical approval will not be required. The results may be published in a peer-reviewed journal or disseminated at relevant conferences. OSF REGISTRATION NUMBER: DOI 10.17605/OSF.IO/WBC7F.