Computational study of the conformational preferences of the (R)-8-amino-pentacyclo[5.4.0.0(2,6).0(3,10).0(5,9)]undecane-8-carboxylic acid monopeptide.
alpha-Amino acids are important building blocks for the synthesis of a large number of bioactive compounds and pharmaceutical drugs. However, a literature survey revealed that no theoretical conformational study of alpha-amino acids with cage carbon frameworks has been performed to date. This paper reports the results of a conformational study on the (R)-8-amino-pentacyclo[5.4.0.0(2,6).0(3,10).0(5,9)]undecane-8-carboxylic acid monopeptide (cage monopeptide), using molecular mechanics and ab initio methods. The in vacuo Ramachandran maps computed using the different parameterizations of the AMBER force field show the C7eq structure as the most favourable conformation, in contrast to the C7ax structure, that is the lowest energy conformation at the ab initio level. Analysis of these maps reveals the helical preference for the monopeptide and provides the potential for the cage residue to be incorporated into constrained peptide analogues.
Bisetty
Krishna
K
Department of Chemistry, ML Sultan Technikon, PO Box 1334, Durban 4000, South Africa.
Gomez-Catalan
Jesus
J
Aleman
Carlos
C
Giralt
Ernest
E
Kruger
Hendrik G
HG
Perez
Juan J
JJ
D000218:Adamantane / Q000031:analogs & derivatives* / Q000737:chemistry*; D000596:Amino Acids / Q000737:chemistry; D002264:Carboxylic Acids / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D009842:Oligopeptides / Q000737:chemistry; D012984:Software; D013237:Stereoisomerism
D000596:Amino Acids; D002264:Carboxylic Acids; D009842:Oligopeptides; D000218:Adamantane