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.
Institute of Biochemistry, Universität Leipzig, Brüderstr. 34, D-04103 Leipzig, Germany.
Michael
M
Haack
Sebastian
S
Enck
Harald
H
Seger
Armin
A
Geyer
Annette G
AG
Beck-Sickinger
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