Amine dehydrogenase-catalyzed reductive amination of prochiral ketones with ammonia is a promising method for the synthesis of optically pure amines in the pharmaceutical and fine chemical industries. However, previously reported amine dehydrogenases show restricted catalytic capacity toward bulky ketones, which limits their widespread applications toward the production of chiral amines. Herein, we expanded the substrate scope of an engineered amine dehydrogenase GkAmDH from Geobacillus kaustophilus via laboratory evolution for the reductive amination of an extensive set of ketones. Several beneficial mutants were identified with a up to 2.2 U mg–1 activity toward bulky benzylacetone, 110-fold higher than that of M0. Using the engineered M3 and M8, structurally diverse bulky chiral amines could be synthesized with up to >99% conversion, >99% ee, and up to 18,900 TON. Among them, two key chiral intermediates used in the synthesis of the drugs medroxalol and dilevalol were produced on a gram scale in up to 85% yield and >99% ee. Additionally, the engineered enzymes M3 and M8 displayed considerable thermostability with a half-life of more than three days at 50 °C. These results demonstrate that these engineered amine dehydrogenases are promising biocatalysts for the synthesis of chiral amines. Molecular dynamics simulations provide insights into how mutations improve the amination activity toward bulky ketones and the thermostability.

The pTEN/AKT/mTOR signaling pathways play a critical role in balancing cell proliferation, differentiation, and survival. Recent studies researched the associations of core genes in the pTEN/AKT/mTOR pathway polymorphisms with the cancer susceptibility; however, the results are inconclusive. Therefore, a systematically meta-analysis was performed to evaluate the association between the five SNPs (mTOR rs2295080 and rs2536, AKT1 rs2494750 and rs2494752, pTEN rs701848) and cancer risk by systematic review of the literature in 31 eligible studies. The results showed a significant decreased risk between rs2295080 TG, GG genotype, and GG/TG genotypes and overall cancer [TG vs.TT: OR(95% CI) = 0.82(0.76, 0.89), GG/TG vs. TT: OR(95% CI) = 0.82(0.76, 0.88), and GG vs. TG/TT: OR(95% CI) = 0.67(0.51, 0.88)] and the subgroup of urinary system cancer and digestive system cancer. Moreover, the SNP rs701848 CC, TC genotype showed significantly increased the overall cancer risk both in dominant model [CC/TC vs. TT: OR(95% CI) = 1.25(1.15, 1.36)] and recessive model [CC vs. TC/TT: OR(95% CI) = 1.20(1.09, 1.32)], and digestive system cancer and urinary system cancer. In addition, AG genotype and GG/AG genotype of rs2494752 was associated with increased risk of cancer. Therefore, this meta-analysis provided genetic risk factors for carcinogenesis and the most valid cancer prevalence estimate for Asian population.

No abstract

No abstract

No abstract