During replication of hepatitis C virus (HCV), the final steps of polyprotein processing are performed by a viral proteinase located in the N-terminal one-third of nonstructural protein 3. The structure of NS3 proteinase from HCV BK strain was determined by X-ray crystallography at 2.4 angstrom resolution. NS3P folds as a trypsin-like proteinase with two beta barrels and a catalytic triad of His-57, Asp-81, Ser-139. The structure has a substrate-binding site consistent with the cleavage specificity of the enzyme. Novel features include a structural zinc-binding site and a long N-terminus that interacts with neighboring molecules by binding to a hydrophobic surface patch.

The structural basis of the RNA selectivity of HCV RdRp was elucidated from its crystal structure. The putative substrate-binding site with a shallow hydrophilic cavity should have ribonucleoside triphosphate (rNTP) as the preferred substrate. We propose that the unique alpha fingers might represent a common structural discriminator of the template-primer duplex that distinguishes between RNA and DNA during the replication of positive single-stranded RNA by viral RdRps. The C-terminal region might exert a regulatory function on the initiation and activity of HCV RdRp.

BackgroundMuscle contraction during short intervals of intense exercise causes oxidative stress, which can play a role in the development of overtraining symptoms, including increased fatigue, resulting in muscle microinjury or inflammation. Recently it has been said that hydrogen can function as antioxidant, so we investigated the effect of hydrogen-rich water (HW) on oxidative stress and muscle fatigue in response to acute exercise.MethodsTen male soccer players aged 20.9 ± 1.3 years old were subjected to exercise tests and blood sampling. Each subject was examined twice in a crossover double-blind manner; they were given either HW or placebo water (PW) for one week intervals. Subjects were requested to use a cycle ergometer at a 75 % maximal oxygen uptake (VO2) for 30 min, followed by measurement of peak torque and muscle activity throughout 100 repetitions of maximal isokinetic knee extension. Oxidative stress markers and creatine kinase in the peripheral blood were sequentially measured.ResultsAlthough acute exercise resulted in an increase in blood lactate levels in the subjects given PW, oral intake of HW prevented an elevation of blood lactate during heavy exercise. Peak torque of PW significantly decreased during maximal isokinetic knee extension, suggesting muscle fatigue, but peak torque of HW didn’t decrease at early phase. There was no significant change in blood oxidative injury markers (d-ROMs and BAP) or creatine kinease after exercise.ConclusionAdequate hydration with hydrogen-rich water pre-exercise reduced blood lactate levels and improved exercise-induced decline of muscle function. Although further studies to elucidate the exact mechanisms and the benefits are needed to be confirmed in larger series of studies, these preliminary results may suggest that HW may be suitable hydration for athletes.

We report a new series of hepatitis C virus NS5B RNA polymerase inhibitors containing a conformationally constrained tetracyclic scaffold. SAR studies led to the identification of 6,7-dihydro-5H-benzo[5,6][1,4]diazepino[7,1-a]indoles (19 and 20) bearing a basic pendent group with high biochemical and cellular potencies. These compounds displayed a very small shift in cellular potency when the replicon assay was performed in the presence of human serum albumin.