Synthetic dipeptides comprising mixtures of enantiomers, diastereomers, or sequential isomers were converted into their N-perfluoroacetyl dipeptide esters (perfluoroacetyl: trifluoroacetyl, pentafluoroacetyl, heptafluorobutyryl; ester: methyl, 1-propyl, 2-propyl, 2,2,2-trifluoroethyl) and analyzed by GC-MS on the chiral stationary phases Chirasil-L-Val and Lipodex-E using helium as carrier gas....

In this presentation, we describe an integrated approach for the molecular basis for sweet taste among dipeptide-based ligands. By comparing the results obtained from X-ray diffraction studies with the conformations from NMR analysis and molecular modeling, we have observed recurring topochemical motifs that agree with previous models for sweet taste. In our examination of the unexplored D zone...

Two novel, asymmetric methanofullerenes are presented, which self-assemble in cyclohexane upon thermal cycling to 80 °C. We show that, through the introduction of a dipeptide sequence to one terminus of the dendritic methanofullerene, it is possible to transform the assembly behavior of these molecules from poorly formed aggregates to high-aspect-ratio nanorods. These nanorods have diameters of...

Time-resolved CIDNP and Laser Flash Photolysis have been applied to the investigation of the kinetics and mechanism of CIDNP formation in the reactions of aza-aromatic dye 2,2′-dipyridyl and protein-related molecules, including N-acetyl derivatives of three amino acids (tryptophan, tyrosine, histidine) the dipeptide tryptophan-tyrosine, and hen egg-white lysozyme in native and denatured states....

The synthesis and biological activity of new conjugates of muramyl dipeptide (MDP) and nor-muramyl dipeptide (nor-MDP) with tuftsin and retro-tuftsin derivatives containing isopeptide bond between ε-amino group of lysine and carboxyl group of simple amino acids such as Ala, Gly and Val are presented. We presumed, based on the cytokine profile, that the examined conjugates of tuftsin and MDP wer...

A syntheses of three new muramyl dipeptide (MDP) analogues related to LK 423 as potential immunomodulators are presented. The dipeptide part of the lead compound was modified by introducing a phosphonamide isostere instead of the amide bond between Lalanine and D-glutamic acid (or D-isoglutamine), yielding new MDP analogues 5 and 9. Furthermore, the amide bond between L-Ala and D-Glu was replac...

An analysis of the nature and distribution of disallowed Ramachandran conformations of amino acid residues observed in high resolution protein crystal structures has been carried out. A data set consisting of 110 high resolution, non-homologous, protein crystal structures from the Brookhaven Protein Data Bank was examined. The data set consisted of a total of 18,708 non-Gly residues, which were...

Muramyl dipeptide, N-acetylmuramyl-L-alanyl-D-isoglutamine, induced adjuvant arthritis in WKA rats when injected in a water-in-oil emulsion prepared with Freund incomplete adjuvant (Difco), but not when emulsified with Drackeol and Arlacel A.

MOTIVATION Standard algorithms for pairwise protein sequence alignment make the simplifying assumption that amino acid substitutions at neighboring sites are uncorrelated. This assumption allows implementation of fast algorithms for pairwise sequence alignment, but it ignores information that could conceivably increase the power of remote homolog detection. We examine the validity of this assum...

A muramyl peptide that induces excess slow-wave sleep in rats, rabbits, and cats has recently been isolated from human urine. We now report that synthetic acetylmuramyl-L-alanyl-D-isoglutamine ("muramyl dipeptide") and its lysyl derivative (acetylmuramyl-L-alanyl-D-isoglutaminyllysine) can mimic the somnogenic effects of the natural peptide. Both compounds are also pyrogenic and may cause other...