Solution Structure of Neuropeptide Tyrosine 13–36, a Y2 Receptor Agonist, as Determined by NMR

Abstract

The three-dimensional structure of neuropeptide tyrosine (NPY) 13 -36, a specific Y2 receptor agonist, has been investigated by two-dimensional 'H-NMR spectroscopy in solution. Analysis of the doublequantum-filtered correlation spectroscopy (DQFCOSY), total correlation spectroscopy (TOCSY) and nuclear Overhauser enhancement spectroscopy (NOESY) spectra provided a complete assignment of the proton signals. The interproton connectivities observed in the NOESY spectra comprised 166 intraresidue and 95 interresidue distance ranges which were used as constraints for molecular modeling by distance geometry, simulated annealing and energy minimization. The optimal structures are characterized by a helical C-terminal fragment Leu30-Tyr36 and a wide loop from Leu17 to Ser22. The structure of NPY 13-36 is analogous to the structure of NPY under the same solvent conditions. Comparison with other reported Y2 agonists suggests that the helical Leu30-Tyr36 fragment is the most critical for activity.Keywords : neuropeptide tyrosine agonist ; three-dimensional structure; NMR; molecular modeling.Neuropeptide tyrosine or NPY is a 36-amino acid peptide belonging to a family of biologically active peptides which includes peptide YY (PYY) and pancreatic polypeptide (PP). NPY is widely distributed in both the central and peripheral nervous systems and produces a variety of effects especially on the feeding behavior, cardiovascular function and anxiety [ l , 21. Its structure is characterized by the presence of five tyrosine and of four proline residues concentrated in a N-terminal polyproline segment.NPY performs its varied biological functions through the interaction with distinct G-protein-coupled receptor subtypes. Responses to Pro34] The three-dimensional structure of NPY has been investigated by two-dimensional 'H-NMR spectroscopy [12-16) and molecular modeling based on the crystal structure of PP [17-191. All investigations agree on the general structure of NPY which is folded in its center forming a hairpin structure with the N-and C-terminal segments in close proximity. The N-terminal polyproline segment (residues 1 -13) is generally disordered and the C-terminal segment (residues 15 -36) is generally helical, [20-221 and 1,1,1,3,3,3-hexa-fluoro-2-('H2)propano1/20 mM aqueous ('HJacetic acid (3 : 7 at pH 2.7) [23]. Recently, NMR data were reported for NPY 13-36 in ('H,)TFE/water (9 : 1) but the three-dimensional structure could not be determined due to resonance overlap [24]. However, the chemical shift values for the NH and a protons are consistent with helical structure.In this study, the structure of the most common Y2 receptor agonist, NPY 13 -36, has been determined by two-dimensional NMR spectroscopy and molecular modeling. Experiments were performed in deuterated dimethylsulfoxide [(2H,)Me,SO], a solvent of medium polarity which should represent the various media in which the peptide can exist and which is not a helix inducer. These conditions allow us to compare the structure of this fragment with our previously repor...

Are Hormones from the Neuropeptide Y Family Recognized by Their Receptors from the Membrane‐Bound State?

“…[61] Other authors have investigated mutants of truncated or cyclized versions of NPY. [62][63][64][65][66] Keire et al also estimated from CD and NMR spectra the helical content of PYY and the highly Y2-subtype-specific PYY fragment PYY . [67] The calculated helicity for PYY is 42 % and for PYY(3-36) is only 23 %, a result showing that the removal of two N-terminal amino acids resulted in major conformational alterations in solution; this observation was confirmed by our own dynamics data on PYY(3-36) (see below).…”

Stabilization of the Helical Structure of Y2-Selective Analogues of Neuropeptide Y by Lactam Bridges

“…The addition of TFE stabilized the helical structure throughout the molecule, as expected, although the structure was not as regular an R-helix in aqueous TFE as the unbridged analogue Ac[Leu 28,31 ]NPY [24][25][26][27][28][29][30][31][32][33][34][35][36] . 27 To stabilize the helical structure throughout the peptide in the absence of TFE would presumably require the introduction of an additional lactam bridge (possibly overlapping the 28/32 bridge) and/or an i to i + 7 covalent link.…”

“…Because we found a helical structure for Ac-cyclo 28/32 -[Ala 24 ,Lys 28 ,Leu 31 ,Glu 32 ]NPY [24][25][26][27][28][29][30][31][32][33][34][35][36] in aqueous TFE and Rist et al 33 described a hairpin structure for the closely related peptide Ac-cyclo 28/32 [Lys 28 ,Glu 32 ]NPY [25][26][27][28][29][30][31][32][33][34][35][36] , which differs from our peptide in lacking the N-terminal Ala and having Ile 31 in place of Leu 31 , a more detailed comparison was called for. We therefore determined the structures of these two peptides, as well as a third lactam-bridged peptide containing Ala 24 and Ile 31 , under solution conditions (30% aqueous TFE, pH 5.0, 308 K) essentially identical to those described by Rist et al 33 As shown in Figure 5, all three peptides adopt similar helical structures except for the N-terminus of peptide II, which is less well-ordered.…”

Adaptogens Stimulate Neuropeptide Y and Hsp72 Expression and Release in Neuroglia Cells

“…It might be speculated that ADAPT contains some other active compound(s) synergistically increasing the expression of NPY. Interestingly tyrosol, salidroside, and NPY contain five tyrosine residues (Labelle et al, 1997), and all have the same p -hydroxyl-methylene residue. The importance the tyrosine moieties for brain receptors binding and NPY activity has been demonstrated (Martel et al, 1990).…”