The self-assembly of various anions (e.g., thiocyanate, nitrite/nitrate, sulfite/sulfate, tetrahalometallates, etc.) with prototypical π-acids (consisting of cyano-and nitrosubstituted pyrazine and benzene, as well as tetracyanoethylene) occurs rapidly and selectively to yield a series of novel one-dimensional structures. The wire-like molecular chains all consist of parallel stacks of π-acids and alternate anions of different sizes and shapes that establish the dihedral angles R and φ sufficient to define these unique structures. Analogy of such linear arrays to nanoscopic wires is reinforced by the protective sheath of countercations that are completely arrayed around the linear cores. The critical feature of these efficient self-assemblies is shown to derive from anion/π-recognitions via charge-transfer forces between the electron-rich anions acting as electron donors and the electron-poor π-acids acting as electron acceptors to spontaneously generate synthons according to Mulliken theory.
C22H14N2O4S2Cu, orthorhombic, Pbcn (no. 60), a = 20.171(7) Å, b = 9.684(3) Å, c = 10.372(4) Å, V = 2025.9(12) Å3, Z = 4, R
gt
(F) = 0.0334, wR
ref
(F
2) = 0.0908, T = 273.15 K.
IL-7 plays vital roles in thymocyte development, T cell homeostasis and the survival of these cells. IL-7 receptor alpha (IL-7R-alpha) on the thymocytes and T cells is rapidly internalized upon IL-7 ligation. Ephrins (EFN) are cell surface molecules and are ligands of the largest family of receptor kinases, Eph kinases. We discovered that T cell-specific double deletion of EFNB1 and EFNB2 (double KO) in mice led to reduced IL-7R-alpha expression in thymocytes and T cells, and that IL-7R-alpha downregulation in double KO CD4 cells upon IL-7 treatment was accelerated. On the other hand, EFNB1 and EFNB2 overexpression in T cell line EL4 cells retarded IL-7R-alpha downregulation. The EFNB1/EFNB2 double KO T cells manifested compromised homeostatic proliferation, which is an IL-7-dependent process. Using fluorescent resonance energy transfer (FRET), we demonstrated that EFNB1 and EFNB2 physically interacted with IL-7R-alpha. Such interaction likely retarded IL-7R-alpha internalization, as EFNB1 and EFNB2 were not subjected to internalization. Therefore, we revealed a novel function of EFNB1 and EFNB2 in stabilizing the IL-7R-alpha expression at the post-translational level, and a previously unknown modus operandi of EFNBs in the regulation of the expression of other vital cell surface receptors.
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