Molecular Modeling of Epithiospecifier and Nitrile-Specifier Proteins of Broccoli and Their Interaction with Aglycones.

Glucosinolates are secondary plant metabolites of Brassicaceae. They exert their effect after enzymatic hydrolysis to yield aglycones, which become nitriles and epithionitriles through the action of epithiospecifier (ESP) and nitrile-specifier proteins (NSP). The mechanism of action of broccoli ESP and NSP is poorly understood mainly because ESP and NSP structures have not been completely characterized and because aglycones are unstable, thus hindering experimental measurements. The aim of this work was to investigate the interaction of broccoli ESP and NSP with the aglycones derived from broccoli glucosinolates using molecular simulations. The three-dimensional structure of broccoli ESP was built based on its amino-acid sequence, and the NSP structure was constructed based on a consensus amino-acid sequence. The models obtained using Iterative Threading ASSEmbly Refinement (I-TASSER) were refined with the OPLS-AA/L all atom force field of GROMACS 5.0.7 and were validated by Veryfy3D and ERRAT. The structures were selected based on molecular dynamics simulations. Interactions between the proteins and aglycones were simulated with Autodock Vina at different pH. It was concluded that pH determines the stability of the complexes and that the aglycone derived from glucoraphanin has the highest affinity to both ESP and NSP. This agrees with the fact that glucoraphanin is the most abundant glucosinolate in broccoli florets.

Association of -765G>C polymorphism of the COX-2 gene with recurrent embryo implantation failure in Southern Chilean women.

BACKGROUND: Embryo implantation failure is considered an important cause of infertility in women undergoing assisted reproductive protocols. Recent studies demonstrated that the cyclooxygenase-2 (COX-2) enzyme is implicated in biosynthesis of prostaglandins and play an important role in the molecular implantation mechanisms. According to this evidence, we evaluated the potential association between the -765G>C (rs20417) polymorphism at the COX-2 gene and the implantation failure susceptibility in a sample of Chilean women. METHODS: A total of 186 unrelated women matched by age were included in the present study, 106 patients (aged 31.9±4.17 y) with no history of successful pregnancy and a diagnosis of infertility undergoing assisted reproductive protocols and 80 healthy controls (aged 31.4 ± 4.05 y). The COX-2 -765G>C gene polymorphism was analyzed by PCR-RFLP. RESULTS: Genotype distribution and allelic frequencies for -765G>C polymorphism of COX-2 gene were significantly different between patients and controls (P=0.004 and P=0.002, respectively). The odds ratio for implantation failure associated to the -765C allelic variant was 2.14 (95% C.I., 1.35-3.39, P=0.00071). CONCLUSION: Our data suggest, by the first time, that the COX-2 -765G>C polymorphism is associated with recurrent implantation failure in Chilean women and may constituted a novel molecular biomarker of reproductive failure.