Structure and optical activity of unsaturated peptides

Pieroni, Osvaldo; Montagnoli, Giorgio; Fissi, Adriano; Merlino, Stefano; Ciardelli, Francesco

doi:10.1021/ja00856a037

Cited by 96 publications

(48 citation statements)

References 4 publications

(10 reference statements)

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“…23 Crystallographic data show that, in APhe residues, the cinnamic moiety is not planar, since the planes of the C = C and the C = 0 double bonds form rather large skew angles. This does not affect appreciably the absorption spectrum, as the carbonyl group plays only an inductive effect.…”

Section: Absorption Spectramentioning

confidence: 99%

Solution structure of peptides containing two dehydro‐phenylalanine residues: A CD investigation

et al. 1993

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The peptides Ac-delta Phe-Ala-delta Phe-NH-Me (1), Ac-delta Phe-Val-delta Phe-NH-Me (2), Ac-delta Phe-Gly-delta Phe-Ala-OMe (3), and Boc-Ala-delta Phe-Gly-delta Phe-Ala-OMe (4), containing two dehydro-phenylalanine (delta Phe) residues, were synthesized and the solution structure investigated in various solvents. The nmr and CD measurements indicate that all the dehydropeptides examined adopt 3(10)-helical conformations in solution. The tripeptides 1 and 2 exhibited an intense negative CD exciton couplet, which was assigned to the right-handed screw sense, while the tetrapeptide 3 displayed a CD couplet having opposite sign, which was assigned to the left-handed helical sense. In the pentapeptide 4 the sense of the helix was found to vary with solvent and temperature, as demonstrated by the sign reversal of the CD spectrum. The right-handed sense dominates in hexafluoro-2-propanol, whereas a left-handed helix prevails in chloroform, acetonitrile and methanol. A crucial role for this behavior is likely to be played by the two alanine residues positioned respectively at the head and tail of the sequence, which favor conformations having opposite screw senses.

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Section: Absorption Spectramentioning

confidence: 99%

Solution structure of peptides containing two dehydro‐phenylalanine residues: A CD investigation

et al. 1993

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“…It has been found that in the solid state a ∆Phe residue of the Z configuration induces β-turns in short sequences [2][3][4][5][6] and a 3 10 -helix in longer ones or peptides with more than one dehydro residue. 4,[7][8][9][10][11][12][13][14][15][16][17][18][19] Similar conformational properties of ∆ Z Phe have been observed in solution by NMR 8,11,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] and CD, 18,19,[27][28][29][30][31][32][33][34][35][36]…”

Section: Introductionmentioning

confidence: 65%

“…The peptides contain a ∆Phe residue which gives a large CD band in that region, at about 280 nm, which is very sensitive to a dehydropeptide conformation. 18,19,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] Thus, this residue is a very good conformational probe in the studies on dehydropeptides. Moreover, Z-p-NA and E-p-NA contain the p-NA group which has been also found to be a useful tool in the conformational studies on peptides.…”

Section: Discussionmentioning

confidence: 99%

“…The spectra of Z-OMe and E-OMe show a large, broad band at 280 nm, similar to those observed for other mono-unsaturated ∆ Z Phe peptides. 35,36,42 It is an intramolecular charge-transfer band originating from the cinnamic chromophore C 6 H 5 C=C-C=O of the ∆Phe residue, from the highest occupied orbital of the electron-donating styryl group to the vacant orbital of the electron-accepting carbonyl group. 35,61 In the case of Z-p-NA and E-p-NA, the ∆Phe residue band at 280 nm is overlapped by a charge-transfer band of the p-NA group at 315 nm.…”

Section: Absorption Spectramentioning

confidence: 99%

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Effect of the ΔPhe residue configuration on a didehydropeptides conformation: A combined CD and NMR study

Lisowski

Jaremko

et al. 2010

Biopolymers

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Conformations of two pairs of dehydropeptides with the opposite configuration of the ∆Phe residue, Boc-Gly-∆ Z Phe-Gly-Phe-OMe (Z-OMe), Boc-Gly-∆ E Phe-Gly-Phe-OMe (E-OMe), BocGly-∆ Z Phe-Gly-Phe-p-NA (Z-p-NA), and Boc-Gly-∆ E Phe-Gly-Phe-p-NA (E-p-NA) were compared on the basis of CD and NMR studies in MeOH, TFE, MeCN, chloroform, and DMSO. The CD results were used as the additional input data for the NMR-based determination of the detailed solution conformations of the peptides. It was found that E-OMe is unordered and Z-OMe, Z-p-NA, and E-p-NA adopt the β-turn conformation. There are two overlapping β-turns in each of those peptides: type II and type III' in Z-OMe and Z-p-NA, and two type III in E-p-NA. The ordered structure-inducing properties of ∆ Z Phe and ∆ E Phe in the peptides studied depend on the Cterminal blocking group. In methyl esters the ∆ Z Phe residue is a strong inducer of ordered conformations whereas the ∆ E Phe one has no such properties. In p-nitroanilides, both isomers of ∆Phe cause the peptides to adopt ordered structures to a similar extent.

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“…The shift of the band I may be induced by high polarity or strong H-bond donating nature of TF A, because this band is assigned to an intramolecular charge-transfer interaction between styryl and carbonyl groups in the A zPhe residue. 34 However, the transition properties in the presence of TF A should be similar to those in the absence of TF A, because the absorption profile did not change essentially in the absence of and presence of TF A. Accordingly, the change of CD spectra with adding TF A can be ascribed to qualitative conformational change induced by TF A.…”

Section: Helical Stabilitymentioning

confidence: 94%

Conformation of Sequential Polypeptide Containing Z-Dehydrophenylalanine Residues

Inai

Ito

Hirabayashi

et al. 1995

Polym J

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ABSTRACT:A sequential polypeptide containing Z-dehydrophenylalanine (~2 Phe) residues, poly[Lys(Z)-~2Phe-Aib], was synthesized to realize a highly stable helical backbone for regularly arranging the fi-substituents of dehydroresidues. The polypeptide was prepared by polymerizing the corresponding tripeptide with diphenylphosphoryl azide and fractionated into different molecular weight (MW) species. The polypeptides showed CD profiles with exciton couplets around 276nm in chloroform, in trimethyl phosphate, and in trifluoroacetic acid, indicating that fi-phenyl groups are arranged regularly along the right-handed helical backbone having high conformational stability. Average main-chain conformations in solution of a series of peptides (X-~2 Phe-Aib). (n=2, 3, 4, and >4) were estimated by considering conformational energies, an9 experimental and theoretical CD amplitudes at the same time. Oligopeptides Boc-(Ala-~2 Phe-Aib).-0Me (n=2---4) were shown to form a right-handed 310-type helix that contains 3.2-3.3 residues per turn. The polypeptide also formed a right-handed helix but, with increasing MWs, this helix deviatt';d from that of oligopeptides and showed a tendency to form an a-type helix.KEY WORDS Z-Dehydrophenylalanine / Sequential Polypeptide / CD Study / Helical Conformation / cc,/j-Dehydroamino acid residues are present naturally in many peptides having biological activity and in some proteins. 1 -5 These residues in (poly)peptides have been found to influence main-chain conformations due to the presence of C" = CP double bonds having inherent structural features: i.e., plarnarity around the C" = cP and trigonal geometry of C". For Z-cc,/j-dehydrophenylalanine (A 2 Phe), this residue favors the formation of P-turn structures in small peptides. 6 portant element for optimally-designing not only P-turn, but also helical backbones. Also, the A 2 Phe residue is expected to have a specific conformational space for its side chain. In particular, side-chain freedom will be smaller than those for naturally occurring amino acids such as Phe, Glu, and Lys, 15 -17 because of prohibited rotation about C" = cP double bonds. Thus, such P-substituted cc,Pdehydroalanines attract much interest as unique residues to provide a rigid and regular molecular frame for arranging P-substituents along a peptide backbone.-NH-C-C0-11

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Structure and optical activity of unsaturated peptides

Cited by 96 publications

References 4 publications

Solution structure of peptides containing two dehydro‐phenylalanine residues: A CD investigation

Solution structure of peptides containing two dehydro‐phenylalanine residues: A CD investigation

Effect of the ΔPhe residue configuration on a didehydropeptides conformation: A combined CD and NMR study

Conformation of Sequential Polypeptide Containing Z-Dehydrophenylalanine Residues

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