Pyridone dipeptide backbone scan to elucidate structural properties of a flexible peptide segment.
Whereas the C-terminal fragment of neuropeptide Y (NPY) has been structurally well-defined both in solution and as membrane-bound, detailed structural information regarding the proline-rich N-terminus is still missing. The systematic variation of each position by a conformationally constrained pyridone dipeptide building block within the amino terminal segment of NPY leads to a systematic receptor subtype selectivity of the neuropeptide. Thereby, the systematic dipeptide scan proved superior to the traditional L-Ala scan because it showed how to modify the N-terminus in order to obtain increasingly more Y1 or Y5 receptor selective ligands. NMR and CD spectroscopic analyses were used to characterize the stepwise rigidification of the N-terminus of NPY when up to three dipeptide building blocks were incorporated by solid-phase peptide synthesis. The pyridone dipeptide increases the hydrophobicity of the amino terminus of NPY, and this allows the tuning of the membrane affinity of NPY. The amphiphilic C-terminal helix of 3-fold-substituted NPY thus becomes visible by selective line broadening in the (1)H NMR. Accordingly, we could structurally characterize protein segments that are too flexible for other methods.
Haack
Michael
M
Institute of Biochemistry, Universität Leipzig, Brüderstr. 34, D-04103 Leipzig, Germany.
Enck
Sebastian
S
Seger
Harald
H
Geyer
Armin
A
Beck-Sickinger
Annette G
AG
D002942:Circular Dichroism; D004151:Dipeptides / Q000737:chemistry; D006801:Humans; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D009478:Neuropeptide Y / Q000031:analogs & derivatives* / Q000737:chemistry*; D010446:Peptide Fragments / Q000138:chemical synthesis* / Q000737:chemistry; D017433:Protein Structure, Secondary; D011728:Pyridones / Q000737:chemistry*; D017476:Receptors, Neuropeptide Y / Q000378:metabolism
D004151:Dipeptides; D008024:Ligands; D009478:Neuropeptide Y; D010446:Peptide Fragments; D011728:Pyridones; D017476:Receptors, Neuropeptide Y