Here we describe a de novo tRNA acylation system, the flexizyme (Fx) system, for the preparation of acyl tRNAs with nearly unlimited selection of amino and hydroxy acids and tRNAs. The combination of the Fx system with an appropriate cell-free translation system allows us to readily perform mRNA-encoded synthesis of proteins and short polypeptides involving multiple non-natural amino acids.
We report a methodology for the ribosomal synthesis of backbone-cyclized peptides involving genetic code reprogramming to introduce one or more nonproteinogenic amino acids. Expression of linear peptides bearing a cysteine-proline dipeptide sequence followed by glycolic acid results in self-rearrangement to a C-terminal diketopiperadine-thioester, which non-enzymatically generates a cyclized peptide. We demonstrate the ribosomal synthesis of several naturally occurring backbone-cyclized peptides and a library based on a bicyclic scaffold, and we identify bioactive sequences by screening and deconvolution.
Ring around the peptides: We demonstrate a new method for the cyclization of peptides that involves the oxidative coupling of 5‐hydroxyindole and benzylamine. After two nonproteinogenic amino acids were incorporated into peptides by reprogramming the genetic code, cyclization took place rapidly upon the addition of K3Fe(CN)6 and generated a conjugated, fluorescent, heterocyclic structure.magnified image
BackgroundHops are the main components of beer that provide flavor and bitterness. Iso-α-acids, the bitter components of beer, have been reported to reduce body fat in humans, but the bitterness induced by effective doses of iso-α-acids precludes their acceptance as a nutrient. The matured hop bitter acids (MHBA) of oxidized hops appear to have a more pleasant bitterness compared to the sharper bitterness of iso-α-acids. While there has been little information concerning the identity of the MHBA compounds and their physiological effects, MHBA was recently found to be primarily composed of oxides derived from α-acids, and structurally similar to iso-α-acids. Here, we investigated the effects of matured hop extract (MHE) containing MHBA on reducing abdominal body fat in healthy subjects with a body mass index (BMI) of 25 to below 30 kg/m2, classified as “obese level 1” in Japan or as “overweight” by the WHO.Trial designA randomized, double-blind, placebo-controlled parallel group study.MethodsTwo hundred subjects (male and female aged 20 to below 65 years with a BMI of 25 or more and less than 30 kg/m2) were randomly assigned to two groups. During a 12-week ingestion period, the subjects in each group ingested daily 350 mL of test-beverage, either containing MHE (with 35 mg MHBA), i.e. the namely active beverage, or a placebo beverage without MHE. The primary endpoint was reduction of the abdominal fat area as determined by CT scanning after continual ingestion of MHE for 12 weeks.ResultsCompared to the placebo group, a significant reduction was observed in the visceral fat area after 8 and 12 w, and in the total fat area after 12 w in the active group. There was also a concomitant decrease in body fat ratio in the active group compared to the placebo group. No adverse events related to the test beverages or clinically relevant abnormal changes in the circulatory, blood and urine parameters were observed in either group.ConclusionsThe present study suggests that continual ingestion of MHE safely reduces body fat, particularly the abdominal visceral fat of healthy overweight subjects.Trial registrationUMIN-CTR UMIN000014185 Electronic supplementary materialThe online version of this article (doi:10.1186/s12937-016-0144-2) contains supplementary material, which is available to authorized users.
Roasted barley extract (RBE, "Mugicha") is a traditional Japanese beverage reported to improve blood viscosity and affect food functionality. RBE is suggested to contain 2,5-diketopiperazines, which are the functional component with neuroprotective and immunostimulatory effects that are produced in food through roasting. In this study, we investigated the effects of RBE on blood circulation, both clinically and in rats. At first, we confirmed five 2,5-diketopiperazine derivatives in RBE by LC-MS analysis. Secondarily, we revealed that RBE affects blood flow in the rat tail and compared the efficacy on rat tail blood flow among five 2,5-diketopiperazines in RBE. Especially, cyclo(d-Phe-l-Pro) was the most effective in increasing blood flow in the rat tail. We also researched the mechanism of cyclo(d-Phe-l-Pro) with rat aorta study. As a result, we confirmed that cyclo(d-Phe-l-Pro) has an effect on vasodilatation through the release of nitric oxide in the vascular endothelium. Finally, we also confirmed that RBE affects cutaneous blood flow and increases skin temperature in humans.
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