ABSTRACT
Hydrophobic stearoyl derivatives of proline-containing di- and tripeptides and their deuterated analogs were synthesized. It was shown by NMR spectroscopy that cis-trans-equilibrium around an X-Pro peptide bond is displaced towards trans-conformers for compounds containing a Ste-Pro fragment as opposed to the compounds containing Boc-Pro or Gly-Pro fragments.
Subject(s)
Dipeptides/chemical synthesis , Oligopeptides/chemistry , Proline/analysis , Stearic Acids/chemistry , Amino Acid Sequence , Dipeptides/chemistry , Magnetic Resonance Spectroscopy , Molecular Sequence DataABSTRACT
The review deals with repeating fragments of amino acid sequences, so-called "motifs", that are important in maintaining structural integrity and/or function of various proteins, especially those interacting with phospholipid aggregates. The occurrence of Phe-Leu-Gly motif characteristic for the amino acid sequence of the primate immuno-deficiency viruses fusion peptides is analysed in various proteins, as well as tripeptide fragments of general formula Xaa-Xah-Gly (Xaa-Phe, Tyr; Xab-hydrophobic amino acids Ala, Val, Leu, Ile) homologous to the above motif and retro-sequences Gly-Xab-Xaa. These tripeptide repeats are characteristic for the amino acid sequences of complex membrane proteins, viral envelope proteins, proteinases and proteins connected with energy transfer or interacting with lipids. These repeats are frequently met in conservative regions of amino acid sequences, in sites readily accessible for other molecules at the boundary of or between structured fragments, this being due to the backbone semi-coiled form's preference in the given amino acid fragment. This protein motif appears to play an important role at the initial stages of the large protein's interaction with the phospholipid membrane.
Subject(s)
Proteins/genetics , Repetitive Sequences, Nucleic Acid , Amino Acid Sequence , Molecular Sequence DataABSTRACT
Peptide Gly-L-Leu-L-Phe and its derivatives were synthesized by the C-end elongation utilizing DCC/HOBT technique and by enzymatic route with the help of papain using esters of N-benzyloxycarbonyl-glycine and -L-leucine as acyl donors have been suggested. The chemical, similarly to the enzymatic, synthesis was not accompanied by racemization. Conditions for HPLC separation and preparative isolation of the enzymatic reaction products were developed.