Structure-activity studies of lGnRH-III through rational amino acid substitution and NMR conformational studies.
 

Structure-activity studies of lGnRH-III through rational amino acid substitution and NMR conformational studies.

http://www.bionmr.com//www.ncbi.nlm....x_FullText.gif Related Articles Structure-activity studies of lGnRH-III through rational amino acid substitution and NMR conformational studies.

Biopolymers. 2012;98(6):525-34

Authors: Pappa EV, Zompra AA, Diamantopoulou Z, Spyranti Z, Pairas G, Lamari FN, Katsoris P, Spyroulias GA, Cordopatis P

Abstract
Lamprey gonadotropin-releasing hormone type III (lGnRH-III) is an isoform of GnRH isolated from the sea lamprey (Petromyzon marinus) with negligible endocrine activity in mammalian systems. Data concerning the superior direct anticancer activity of lGnRH-III have been published, raising questions on the structure-activity relationship. We synthesized 21 lGnRH-III analogs with rational amino acid substitutions and studied their effect on PC3 and LNCaP prostate cancer cell proliferation. Our results question the importance of the acidic charge of Asp? for the antiproliferative activity and indicate the significance of the stereochemistry of Trp in positions 3 and 7. Furthermore, conjugation of an acetyl-group to the side chain of Lys? or side chain cyclization of amino acids 1-8 increased the antiproliferative activity of lGnRH-III demonstrating that the proposed salt bridge between Asp? and Lys? is not crucial. Conformational studies of lGnRH-III were performed through NMR spectroscopy, and the solution structure of GnRH-I was solved. In solution, lGnRH-III adopts an extended backbone conformation in contrast to the well-defined ?-turn conformation of GnRH-I.


PMID: 23203758 [PubMed - indexed for MEDLINE]



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