The non-structural protein 5A (NS5A) of hepatitis c virus interacts with the SH3 domain of human Bin1 using non-canonical binding sites

The hepatitis C virus (HCV) is a major human pathogen that causes severe diseases such as chronic hepatitis, liver cirrhosis and finally hepatocellular carcinoma. Although no enzymatic activity could be attributed yet to the HCV non-structural protein 5A (NS5A), it is indispensable for viral replication and particle assembly. Furthermore, it is associated with a variety of cellular pathways, although their relevance for viral pathogenesis still has to be elucidated. To fulfil its function NS5A interacts with a large number of different proteins including both viral and human ones. NS5A is organized into three domains, which are connected via two low complexity sequences (LCS). The first domain is highly conserved among different HCV genotypes and forms a well-defined globular structure [1]. The domains 2 (D2) and 3 (D3) are less conserved and intrinsically disordered. Nonetheless, three segments in LCS-I and D2 show significant propensities to adopt a-helical structures as could be shown by nuclear magnetic resonance (NMR) chemical shift and 15 N relaxation data [2]. The LCS-II connecting D2 and D3 contains two directly neighbored class II PxxP-motifs, which are important for interactions with Src homology 3 (SH3) domains. SH3 domains mediate protein-protein interactions, often via binding to polyproline II helices. Recent studies also revealed alternative binding mechanisms, mainly involving helical motifs and positively charged amino acid residues. The SH3 domain of the bridging integrator 1 (Bin1) is known to interact with NS5A not only via its PxxP-motifs, but also via two non-canonical binding sites, which will be further described here [3]

Attosecond electron thermalization by laser-driven electron recollision in atoms

Nonsequential multiple ionization of atoms in intense laser fields is initiated by a recollision between an electron, freed by tunneling, and its parent ion. Following recollision, the initial electron shares its energy with several bound electrons. We use a classical model based on rapid electron thermalization to interpret recent experiments. For neon, good agreement with the available data is obtained with an upper bound of 460 attoseconds for the thermalization time.Comment: 5 pages revtex and 4 figures (eps files

Is Workstyle a Mediating Factor for Pain in the Upper Extremity Over Time?

Introduction Upper extremity musculoskeletal disorders influence workers’ quality of life. Workstyle may be one factor to deal with in workers with pain in the upper extremity. The objective of this study was to determine if workstyle is a mediating factor for upper extremity pain in a changing work environment of office workers over time. Methods Office workers with upper extremity pain filled out a Workstyle questionnaire (WSF) at baseline (n = 110). After 8 and 12 months follow-up assessment took place. Participants were divided into a good and an adverse workstyle group at baseline. The presence of upper extremity pain in both groups was calculated and relative risks were determined. Chi-square tests were used. Results Eight months after baseline, 80% of the adverse and 45% of the good workstyle group reported pain. The relative risk (RR) of having upper extremity pain for the adverse compared to the good workstyle group was 1.8 (95% CI 1.08–2.86) (P = 0.055). Twelve months after baseline, upper extremity pain was more often presented in the adverse workstyle compared to the good workstyle group (RR = 3.0, (95% CI 1.76–5.11), P = 0.003). Twelve months after baseline, 100% of the adverse workstyle group and 33% of the good workstyle group reported pain in the upper extremity. Conclusion Workstyle seems to be a mediating factor for upper extremity pain in office workers in a changing work environment. It is recommended to assess workstyle among office workers with upper extremity pain, and to include workstyle behaviour in treatments

Single ionization of atoms in intense laser pulses: Evolution from multiphoton to tunnel ionization

We present results of high resolution fully differential measurements on single ionization of He, Ne, and Ar by 7-25 fs linearly polarized 800nm laser pulses at intensities of up to 2.1015 W/cm2. Using a 'Reaction-Microscope' we were able to trace signatures of multiphoton ionization deep into the tunnelling regime. Surprisingly, in the low-energy electron spectra we observed several features (absence of the ponderomotive shifts, splitting of the peaks, their degeneration for few-cycle laser pulses) typical for resonantly-enhanced ionization. Other remarkable features, as the sharp cusp-like momentum distributions in the direction perpendicular to the laser field or the observed minima at zero longitudinal momentum for He and Ne, can be reproduced by semiclassical models, where the electron motion in the combined laser and Coulomb field is treated classically after the tunnelling