TY  - JOUR
A1  - Lamping, Matthias
A1  - Grell, Yvonne
A1  - Geyer, Armin
T1  - Synthesis and conformational analysis of an expanded cyclic ketoxime-hexapeptide
JF  - Journal of Peptide Science
N2  - n this work the synthesis of a linear hexapeptide with a hydroxylamine functionality at the N‐terminus and a ketone instead of the carboxylic acid at the C‐terminus is described. Cyclization by ketoxime formation yields the 19‐membered ring‐expanded cyclic hexapeptide cyclo[Goly‐Val‐Ala‐Pro‐Leu‐Kly] which adopts a main conformer with two intramolecular hydrogen bonds. The hydrolytic stability of a ketoxime lies between the inert amide and the labile imine. The substitution of an amide bond for an iminium bond transforms the irreversible macrocyclization into a reversible process, but macrocyclic imines are difficult to isolate because they are prone to hydrolysis. The enhanced chemical stability of the ketoxime justifies its application in ligation protocols. The detailed NMR analysis of a ketoxime linkage presented here identifies its local conformational preferences in a constrained peptide environment.
KW  - Peptide
KW  - Cyclization
KW  - NMR
KW  - Oxime
KW  - Conformation
Y1  - 2016
U6  - http://dx.doi.org/10.1002/psc.2873
SN  - 1099-1387
VL  - 22
IS  - 4
SP  - 228
EP  - 235
ER  -