Neurotensin (NT) is a neurohormone and/or neuromodulator containing 13 amino acid residues. Neurotensin receptors (NTR) are transmembrane receptors that bind neurotensin. The active fragment of neurotensin is 8-13 (RRPYIL). The main drawback in the use of NT or any other endogenous peptide as a drug is extremely short half-life as a result of their rapid degradation by the action of peptidases. To overcome this problem, various neurotensin analogues were synthesized, which include linear peptides, cyclic peptides and nonpeptide molecules. Chemical modification of the native peptide, however, may result in a radical change in the receptor affinity and specificity. The purpose of this work is to identify interactions between newly synthesized neurotensin analogues and neurotensin receptor (NTR1) and to establish the relationship between structure and action using computational methods. All new analogues were synthesized using SPPS. The results of docking shows that the tested analogues of neurotensin bind in the active site of the receptor, but significantly weaker than NT. Replacement of arginine residue in the second position with canavanine strongly increases the total energy of the ligand-receptor complex, therefore it is more unstable than the complex NT/NTR1.
