Remarkable shifts of C -H and O-H stretching frequencies and stability of complexes of formic acid with formaldehydes and thioformaldehydes.

Thirty-six stable complexes of formic acid with formaldehydes and thioformaldehydes were determined on the potential energy surface, in which the XCHO···HCOOH complexes are found to be more stable than the XCHS···HCOOH counterparts, with X = H, F, Cl, Br, CH , NH . All complexes are stabilized by hydrogen bonds, and their contribution to the total stabilization energy of the complexes increases in going from C-H···S to C-H···O to O-H···S and finally to O-H···O. Remarkably, a significant blueshift of C -H bond by 81-96 cm in the C -H···O hydrogen bond has hardly ever been reported, and a considerable redshift of O-H stretching frequency by 206-544 cm in the O-H···O/S hydrogen bonds is also predicted.

Diphenylhexatriene membrane probes DPH and TMA-DPH: A comparative molecular dynamics simulation study.

Fluorescence spectroscopy and microscopy have been utilized as tools in membrane biophysics for decades now. Because phospholipids are non-fluorescent, the use of extrinsic membrane probes in this context is commonplace. Among the latter, 1,6-diphenylhexatriene (DPH) and its trimethylammonium derivative (TMA-DPH) have been extensively used.

Effect of amphipathic HIV fusion inhibitor peptides on POPC and POPC/cholesterol membrane properties: a molecular simulation study.

T-20 and T-1249 fusion inhibitor peptides were shown to interact with 1-palmitoyl-2-oleyl-phosphatidylcholine (POPC) (liquid disordered, ld) and POPC/cholesterol (1:1) (POPC/Chol) (liquid ordered, lo) bilayers, and they do so to different extents. Although they both possess a tryptophan-rich domain (TRD), T-20 lacks a pocket binding domain (PBD), which is present in T-1249. It has been postulated that the PBD domain enhances FI interaction with HIV gp41 protein and with model membranes.