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β ‐Peptide Conjugates: Syntheses and CD and NMR Investigations of β / α ‐Chimeric Peptides, of a DPA‐ β ‐Decapeptide, and of a PEGylated β ‐Heptapeptide
Author(s) -
Gardiner James,
Mathad Raveendra I.,
Jaun Berhard,
Schreiber Jürg V.,
Flögel Oliver,
Seebach Dieter
Publication year - 2009
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200900325
Subject(s) - chemistry , peptide , pegylation , amino acid , conjugate , stereochemistry , peptidomimetic , proton nmr , peg ratio , combinatorial chemistry , organic chemistry , biochemistry , polyethylene glycol , mathematical analysis , mathematics , finance , economics
β 3 ‐Peptides consisting of six, seven, and ten homologated proteinogenic amino acid residues have been attached to an α ‐heptapeptide (all d‐ amino acid residues; 4 ), to a hexaethylene glycol chain (PEGylation; 5c ), and to dipicolinic acid (DPA derivative 6 ), respectively. The conjugation of the β ‐peptides with the second component was carried out through the N‐termini in all three cases. According to NMR analysis (CD 3 OH solutions), the ( M )‐ 3 14 ‐helical structure of the β ‐peptidic segments was unscathed in all three chimeric compounds ( Figs. 2, 4 , and 5 ). The α ‐peptidic section of the α / β ‐peptide was unstructured, and so was the oligoethylene glycol chain in the PEGylated compound. Thus, neither does the appendage influence the β ‐peptidic secondary structure, nor does the latter cause any order in the attached oligomers to be observed by this method of analysis. A similar conclusion may be drawn from CD spectra ( Figs. 1, 3 , and 5 ). These results bode well for the development of delivery systems involving β ‐peptides.