Synthesis and conformations of somatostatin-related cyclic hexapeptides incorporating specific .alpha.- and .beta.-methylated residues

He, Ya-bo; Ziwei-Huang,; Raynor, K.; Reisine, Terry; Goodman, Murray

doi:10.1021/ja00071a019

Cited by 59 publications

(61 citation statements)

References 2 publications

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“…NMR studies by Kessler et al (1983) also indicated a type II'/3-turn. Huang et al (1992) and He, Huang, Raynor, Reisine & Goodman (1993), using 500MHz two-dimensional NMR, binding studies and conformational analysis of methylated derivatives, showed that although the side chains are conformationally flexible, the biologically active conformation of this cyclic hexapeptide probably involves the trans rotamer of D-Trp 8 and the gauche-(g-) rotamer of Lys 9.…”

Section: Introductionmentioning

confidence: 99%

Structure of octreotide, a somatostatin analogue

Pohl¹,

Heine²,

Sheldrick³

et al. 1995

Acta Cryst D

122

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Octreotide, a synthetic somatostatin analogue, is an octapeptide with one disulfide bridge. Crystals of octreotide are orthorhombic, space group P212121, a = 18.458 (5), b = 30.009 (7), c = 39.705 (27) A, with three molecules of octapeptide, one ordered oxalate dianion and 52 water molecules in the asymmetric unit. Complete protonation of the NH2 groups (as assumed in the refinement) would require three oxalate dianions in the asymmetric unit for charge neutrality; a chemical analysis indicated that four are present. In either case they are so disordered that they cannot be distinguished from the water molecules. The 18 951 unique reflections (Rsy m = 0.026) used for structure solution and refinement were recorded with the EMBL imaging-plate scanner using synchrotron radiation. The structure was solved by Patterson interpretation, locating the three disulfide bridges, followed by tangent phase expansion and EFourier recycling. The anisotropic refinement against all F 2 data between 1.04 and 10.0 A resolution by blocked restrained full-matrix least-squares techniques converged to a conventional R index based on F of 0.084 [I > 2a(/) and 10.0 > d > 1.04 A] and wR2, the weighted R-index on F 2, of 0.246 (for all data). One peptide molecule adopts a flat ~-sheet structure; the other two possess different irregular backbone conformations, but are similar to each other. All three molecules have a distorted type II'/3-turn around the o-Trp-Lys region, but exhibit different sidechain conformations. The crystal structure is stabilized by a network of inter-and intramolecular hydrogen bonds.

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Section: Introductionmentioning

confidence: 99%

Structure of octreotide, a somatostatin analogue

Pohl¹,

Heine²,

Sheldrick³

et al. 1995

Acta Cryst D

122

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show abstract

“…Goodman et al suggested the bent conformation of the peptide as the bioactive conformation, which is stabilized by the two g turns about Phe 7 and Thr 10 . [31] This bent conformation results in the deep insertion of the analogue is less active than MePhe 11 . This result gives an indication of the importance of the spatial orientation of Phe 11 .…”

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confidence: 99%

Improving Oral Bioavailability of Peptides by Multiple N‐Methylation: Somatostatin Analogues

et al. 2008

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Full methyl jacket? A complete library of the N‐methylated somatostatin cyclopeptidic analogue Veber–Hirschmann peptide cyclo(‐PFwKTF‐) has been prepared with the aim of improving its bioavailability. Several analogues from the library were found to bind to the somatostatin receptor in the nanomolar range and one of them shows a significant oral bioavailability of 10 %. Conformational analysis shows that N‐methylation is allowed at specific positions without affecting the bioactive conformation.

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“…Naturally isolated cyclic peptides have become increasingly important because of their wide range of pharmacological activities and interesting chemical structures (He et al, 1993;Wipf, 1995). A variety of active anticancer agents are derived from marine sponges, plants and terrestrial microorganisms (Blunt et al, 2009;Zheng et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Total synthesis and anticancer activity of a cyclic heptapeptide from marine sponge using water soluble peptide coupling agent EDC

Anand¹,

Alagar

Ranjitha³

et al. 2019

Arabian Journal of Chemistry

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Present investigation comprises of synthesis of a novel proline containing cyclic heptapeptide -Euryjanicin A, which was previously isolated from the marine spongeProsuberites laughlini. Naturally isolated cyclic heptapeptide was synthesized using solution phase peptide technique. All the coupling reactions were performed at room temperature via 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) -coupling reagent and triethylamine (Et 3 N) -base. The chemical structure of the finally synthesized cyclic heptapeptide was elucidated using FTIR, 1 H & 13 C NMR and mass spectral data, as well as elemental analyses. The newly synthesized peptide was subjected to anticancer activity against HeLa (Human Colon) cancer cell line and showed potent anticancer activity. ª 2015 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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Synthesis and conformations of somatostatin-related cyclic hexapeptides incorporating specific .alpha.- and .beta.-methylated residues

Cited by 59 publications

References 2 publications

Structure of octreotide, a somatostatin analogue

Structure of octreotide, a somatostatin analogue

Improving Oral Bioavailability of Peptides by Multiple N‐Methylation: Somatostatin Analogues

Total synthesis and anticancer activity of a cyclic heptapeptide from marine sponge using water soluble peptide coupling agent EDC

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