Study of conformational properties of solid phase synthesized ovine kisspeptin-14 using Circular Dichroism spectroscopy

Abstract

<span style="font-size:9.0pt;font-family: " times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-GB">Kisspeptins are peptide products of Kiss-1 gene and have been substantially associated with the initiation of puberty by virtue of their ability to cause pulsatile release of GnRH. Kisspeptin consists of 54 amino acids domain called metastin and its biological activity may be localized to the C-terminal (C-10, C-13, and C-14) segments. Kisspeptin binds to its cognate receptor GPR54 in the hypothalamic neurons and it is a G-coupled membrane receptor. This study is an attempt to understand the tentative conformation of the peptides in its native membrane mimicking environment. A 14 amino-acid derivative of kisspeptin (Asp-58-Val59-Ser60-Ala61-Tyr62-Asn63-Trp64-Asn65-Ser66-Phe67-Gly68-Leu69-Arg70-Tyr71NH2) was synthesized by f-moc (9-fluorenyl methoxy carbonyl) solid phase synthesis strategy. The synthetic peptide was cleaved and purified by Reverse phase-HPLC. CD spectroscopic analysis of secondary structure of the peptide revealed random coil disordered conformation in the aqueous environment. However, the peptide adopted more ordered β-sheet conformation in the solvents such as TFE and HFIP.</span>