No abstract

Background:The bacteria effector Tae4 is injected into the recipient cells to kill them and the immunity protein Tai4 is produced to inactivate Tae4. Results: Tae4 displays a papain-like fold, and Tai4 dimer is responsible for inhibiting Tae4 activity. Conclusion:The inactivation of Tae4 is required by collaboration of both subunits of Tai4 dimer. Significance: Our results add new insights into the effector-immunity interaction module.

EuFe 2 As 2 is a member of the ternary iron arsenide family. Similar to BaFe 2 As 2 and SrFe 2 As 2 , EuFe 2 As 2 exhibits a clear anomaly in resistivity near 200 K. Here we report the discovery of superconductivity in Eu 0.7 Na 0.3 Fe 2 As 2 by partial substitution of the europium site with sodium. ThCr 2 Si 2 tetragonal structure, as expected for EuFe 2 As 2 , is formed as the main phase for the composition Eu 0.7 Na 0.3 Fe 2 As 2 .Resistivity measurement reveals that the transition temperature T c as high as 34.7 K is observed in this compound. The rate of T c suppression with the applied magnetic field is 3.87 T / K, giving an extrapolated zero-temperature upper critical field of 90 T. It demonstrates a very encouraging application of the new superconductors.