Micelle-bound conformations of neurohypophyseal hormone analogues modified with a Cα-disubstituted residue: NMR and molecular modelling studies.
In this study, by applying a combined approach of NMR measurements and molecular modelling, the conformations and the interactions with membrane-like environment of five arginine vasopressin (AVP) or oxytocin (OT) analogues modified with Cα-disubstituted cis-1-amino-4-phenylcyclohexane-1-carboxylic acid in position 2 have been determined. In addition, the AVP analogues were prepared in N-acylated forms with various bulky acyl groups. All of the peptides studied interacted with the mixed dodecylphosphocholine:sodium dodecyl sulphate micelle, providing a model of biological membrane. A different polarities of the AVP- and OT-like peptides resulted in their different position relative to the micelle surface. Thus, the arrangement of the former was nearly perpendicular, whereas the latter was rather parallel to the micelle's surface. Moreover, the results of our studies have shown that the binding sites for antagonists may be overlapped with that for agonists, as well as it may be quite different. Nevertheless, the aromatic-aromatic contacts represent the most important interactions for antagonists, whereas the hydrophilic interactions seem to be crucial for agonists.
Faculty of Chemistry, University of Gdańsk, Sobieskiego 18, 80-952, Gdańsk, Poland. milka@chem.univ.gda.pl
Emilia
E
Sikorska
Anna
A
Kwiatkowska
D000595:Amino Acid Sequence; D001127:Arginine Vasopressin / Q000031:analogs & derivatives / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry* / Q000378:metabolism; D003510:Cyclohexanes / Q000737:chemistry* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D010121:Oxytocin / Q000031:analogs & derivatives / Q000737:chemistry*; D011487:Protein Conformation; D013329:Structure-Activity Relationship
C506369:1-amino-4-phenylcyclohexane-1-carboxylic acid; D002264:Carboxylic Acids; D003510:Cyclohexanes; D008823:Micelles; D001127:Arginine Vasopressin; D010121:Oxytocin