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Strongly altered receptor binding properties in PP and NPY chimeras are accompanied by changes in structure and membrane binding.

Abstract：

:Neuropeptide Y (NPY) and the pancreatic polypeptide (PP) are members of the neuropeptide Y family of hormones. They bind to the Y receptors with very different affinities: Whereas PP is highly selective for the Y(4) receptor, NPY displays highest affinites for Y(1), Y(2), and Y(5) receptor subtypes. Introducing the NPY segment 19-23 into PP leads to an increase in affinity at the Y(1) and Y(2) receptor subtypes whereas the exchange of this segment from PP into NPY leads to a large decrease in affinity at all receptor subtypes. PP displays a very stable structure in solution, with the N terminus being back-folded onto the C-terminal alpha-helix (the so-called PP-fold). The helix of NPY is less stable and the N terminus is freely diffusing in solution. The exchange of this segment, however, does not alter the PP-fold propensities of the chimeric peptides in solution. The structures of the phospholipid micelle-bound peptides serving to mimic the membrane-bound species display segregation into a more flexible N-terminal region and a well-defined alpha-helical region. The introduction of the [19-23]-pNPY segment into hPP leads to an N-terminal extension of the alpha-helix, now starting at Pro(14) instead of Met(17). In contrast, a truncated helix is observed in [(19)(-)(23)hPP]-pNPY, starting at Leu(17) instead of Ala(14). All peptides display moderate binding affinities to neutral membranes (K(assoc) in the range of 1.7 to 6.8 x 10(4) mol(-)(1) as determined by surface plasmon resonance) with the differences in binding being most probably related to the exchange of Arg-19 (pNPY) by Glu-23 (hPP). Differences in receptor binding properties between the chimeras and their parental peptides are therefore most likely due to changes in the conformation of the micelle-bound peptides.

journal_name

Biochemistry

journal_title

Biochemistry

authors

Lerch M,Kamimori H,Folkers G,Aguilar MI,Beck-Sickinger AG,Zerbe O

doi

10.1021/bi0501232

subject

Has Abstract

pub_date

2005-06-28 00:00:00

pages

9255-64

issue

eissn

0006-2960

issn

1520-4995

journal_volume

pub_type

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Strongly altered receptor binding properties in PP and NPY chimeras are accompanied by changes in structure and membrane binding.