RESUMO
Glycosylation is one of the most common post-translational modifications of proteins, which plays essential roles in regulating the biological functions of proteins. Efficient and versatile methods for the synthesis of homogeneous and well-defined N- and O-glycans remain an urgent need for biological studies and biomedical applications. Despite their structural complexity, tremendous progress has been made in the synthesis of N- and O-glycans in recent years. This review discusses some recent advances in the enzymatic and chemoenzymatic synthesis of N- and O-glycans.
Assuntos
Polissacarídeos , Proteínas , Glicosilação , Polissacarídeos/química , Proteínas/metabolismo , Processamento de Proteína Pós-TraducionalRESUMO
Four new analogues of brefeldin A named 7, 7-dimethoxybrefeldin C (3), 6ß-hydroxybrefeldin C (4), 4-epi-15-epi-brefeldin A (5), 4-epi-8α-hydroxy-15-epi-brefeldin C (6), together with four known analogues (1, 7-9) were isolated from a fermentation of the sediment-derived fungus Penicillium sp. DT-F29. The structures of these compounds were elucidated on the basis of extensive spectroscopic and chemical methods. In the bioactivity assays, only compounds 1 and 8 showed significant inhibitory activities against human lung adenocarcinoma cell. In addition, compound 1 was first reported for the potent ability to reactivate latent HIV with EC50 value of 0.03 µM.
Assuntos
Fármacos Anti-HIV/farmacologia , Antineoplásicos/farmacologia , Brefeldina A/análogos & derivados , Penicillium/química , Fármacos Anti-HIV/química , Antineoplásicos/química , Linhagem Celular Tumoral , Avaliação Pré-Clínica de Medicamentos , Sedimentos Geológicos/microbiologia , Humanos , Estrutura MolecularRESUMO
This study was aimed to investigate the distribution feature of HLA-DR/DQ gene linkage disequilibrium in Chinese Han population and to improve the accuracy of HLA matching results. Genotyping of HLA-DR and HLA-DQ gene locus was performed using PCR-SSP typing in Chinese Han population receiving kidney transplantation. The results showed that there were 29 new linkage combinations in 1799 patients, in which DR13-DQ5, DR11-DQ8 and DR8-DQ8 were discovered for 11, 8 and 7 times respectively while DR9-DQ8, DR12-DQ6 and DR14-DQ4 were both discovered for 6 times. The linkage disequilibrium parameters of these haplotypes were negative, showing that these linkages were uncommon. It is concluded that this study not only enriches the classical HLA-DR/DQ linkage combinations, but also indicates the national relevance of combination distribution, and it has great importance in improving the accuracy of HLA matching experiments and reducing unnecessary repeated work.