Interaction of Delta Sleep–Inducing Peptide and Its Analogues with Cellular Membranes: A Structure–Function Analysis

I. I. Mikhaleva ^{a #} G. T. Rikhireva ^b , I. A. Prudchenko ^a , and I. N. Golubev ^c

^# Phone: +7 (495) 335-5366; e-mail: imikha@ibch.ru

^a Shemyakin--Ovchinnikov Institute of Bioorganic Chemistry , Russian Academy of Sciences , ul. Miklukho-Maklaya 16/10, Moscow , 117997 Russia

^b Semenov Institute of Chemical Physics, Russian Academy of Sciences , ul. Kosygina 4, Moscow , 117977 Russia

^c State Research Institute of Organic Chemistry and Technology, sh . Entuziastov 23, Moscow , 111024 Russia

Received October 5, 2005; in final form, October 12, 2005

Abstract: The possibility of a correlation between the membrane properties of the delta sleep–inducing peptide (DSIP) and its analogues and their biological activity in vivo was examined by a comparative study of the membrane effects of these peptides. The peptides exhibiting biological activity in vivo were shown to cause a statistically reliable disordering of lipids in thrombocyte plasma membranes similar to the effect of DSIP. The membrane effect of the D-Val², D-Tyr², and Tyr¹,Pro² analogues of DSIP had the same bimodal dose dependence characteristic of natural DSIP. Only a slight nonspecific lipid disordering was registered for Trp-Asp-Ala-Ser-Gly-Glu, a biologically inactive hexapeptide analogue. These results indicate a correlation between the biological activity of the peptides during in vivo tests and their membrane properties in vitro. The structure–function relationship was studied within the group of DSIP analogues examined in vitro. The DSIP modeling effect, especially pronounced under the action of stress factors, was suggested to be directly associated with the ability of DSIP to change the dynamic structure of biological membranes.

Key words: DSIP, delta sleep–inducing peptide, analogues; ESR ; human thrombocytes; order parameter; plasma membranes; paramagnetic probes

Russian Journal of Bioorganic Chemistry 2006, 32 (2):160-165