Crystal and molecular structure of S-deoxo[Ile3]amaninamide: a synthetic analog of Amanita toxins

Shoham, G.; Rees, Douglas C.; Lipscomb, W. N.; Zanotti, G.; Wieland, Theodor

doi:10.1021/ja00328a051

Cited by 32 publications

(33 citation statements)

References 2 publications

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“…The cyclic octapeptide backbone found here also approximates to that found in amanitin analogs which like cyclo-bis (-L-Cys-Gly-L-Pro-L-Phe-) are also potentially constrained by bridging side chains (Kostansek, Lipscomb, Yocum & Thiessen, 1978;Shoham, Rees, Lipscomb, Zanotti & Wieland, 1984). This result for a monocyclic molecule indicates an intrinsically stable cyclic octapeptide backbone type.…”

Section: C_ '--N--ca--c/supporting

confidence: 72%

Conformation of cyclic octapeptides. VI. Structure of cyclo-bis-(-L-alanyl-glycyl-L-prolyl-L-phenylalanyl-) tetrahydrate

Bhandary¹,

Kopple²

1991

Acta Crystallogr C

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Abstract. C38Ha8N808.4H20, Mr=816"9, monoclinic, P2t, a= 10-381 (1), b= 13-273 (1), c= 15.742 (1) ~,, /3 = 101.83 (1) °, V = 2123.1 A 3, Z = 2, Dx = 1-278 g cm -3, A(Cu Ka) = 1.5418/~, p, = 7.6 cm -~, F(000)= 872, R = 0.035, wR = 0-045 for 3497 reflections [I> 2~r(/)], 4552 unique reflections measured. The synthetic cyclic octapeptide crystallizes from water/methanol solution as a tetrahydrate and the crystals are isomorphous to those of the disulfide-bridged cystine analog cyclo-bis (-L-Cys-

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Section: C_ '--N--ca--c/supporting

confidence: 72%

Conformation of cyclic octapeptides. VI. Structure of cyclo-bis-(-L-alanyl-glycyl-L-prolyl-L-phenylalanyl-) tetrahydrate

Bhandary¹,

Kopple²

1991

Acta Crystallogr C

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“…As 2'-indolylthioethers the S-deoxo compounds If-lm exhibit u.v.-absorption spectra identical to those of the phallotoxins. The addition of an (R)-oxygen atom to the sulfur bridge does not alter the conformation of the molecule, as already proven by X-ray structure analysis of the analogue le (9). The CD spectra (Fig.…”

supporting

confidence: 65%

ChemInform Abstract: Synthesis of Analogues of Amaninamide, an Amatoxin from the White Amanita Virosa Mushroom.

1988

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“…The downfield shift of D-Ala-8(CO) would then result from a H-bridge to its own N H forming a C,-bend. So far only limited experimental evidence for such structure exists [30] [31]. In the X-ray structure the D -A~~-~ ( N H ) is involved in a H-bond to MeLeu-6(CO) forming a CP structure (inverse y-turn, y').…”

mentioning

confidence: 99%

Peptide conformations. Part 31. The conformation of cyclosporin a in the crystal and in solution

Loosli¹,

Kessler²,

Oschkinat³

et al. 1985

Helvetica Chimica Acta

347

265

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The all-light-atom X-ray crystal-structure analysis of cyclosporin A (l), a cyclic undecapeptide containing seven N-methylated amino acids, reveals a conformation very similar to that of the previously analysed iodo derivative which is characterised by a twisted P-pleated sheet involving the residues Me-Val-1 1, MeBmt-1, Abu-2, Sar-3, MeLeu-4, Val-5, MeLeu-6, and Ala-7. The@-bend at Sar-MeLeu-4 is of type II', and the loop of the residual amino acids involves a cis-peptide bond between MeLeu-9 and MeLeu-10. The NH proton of D-Ala-8 closes a $-bend with a H-bond to the MeLeu-6 CO group. The crystal was grown from acetone. A closely similar backbone conformation in apolar solvents such as CDCl, or C6D6 has been derived from the interpretation of the NMR spectral parameters (homo-and heteronuclear NOE effects, coupling constants, chemical-shift values of the C-, H-, and N-atoms). A minor variation in the backbone conformation between crystal and solution is observed in the region of o-Ala-8, where in solution a 3-center H-bond is established between the NH of D-Ala-8 und the carbonyl 0-atoms of both MeLeu-6 ($-turn) and o-Ala-8 (C5-bend). A recently proposed technique to identify intramolecular H-bond via heteronuclear NOE from NH proton to carbonyl C-atoms is critically analysed. The main difference between crystal and solution conformations lies in the orientation of the side chains of the unusual amino acid MeBmt kl = f60" in solution, -168" in the crystal) and of MeLeu-10 k1 = -60" in solution, +60' in the crystal). The differences in crystal and solution are caused by the break ofthe intermolecular H-bond of the OH group of MeBmt on dissolution of the crystal. The bifurcated H-bond ofo-Ala-8 twists the backbone in this region. Molecular modeling demonstrates that this is the origin of the change in the side chain conformation of MeLeu-10. The intramolecular flexibility in the crystal indicated by the thermal parameters obtained from the X-ray refinement, and in solution by an analysis of spin-lattice relaxation times in the NMR experiments, indicate a fairly rigid backbone and fixed conformations for all the side chains except for that of Abu-2 and the distal atoms of MeBmt.

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Crystal and molecular structure of S-deoxo[Ile3]amaninamide: a synthetic analog of Amanita toxins

Cited by 32 publications

References 2 publications

Conformation of cyclic octapeptides. VI. Structure of cyclo-bis-(-L-alanyl-glycyl-L-prolyl-L-phenylalanyl-) tetrahydrate

Conformation of cyclic octapeptides. VI. Structure of cyclo-bis-(-L-alanyl-glycyl-L-prolyl-L-phenylalanyl-) tetrahydrate

ChemInform Abstract: Synthesis of Analogues of Amaninamide, an Amatoxin from the White Amanita Virosa Mushroom.

Peptide conformations. Part 31. The conformation of cyclosporin a in the crystal and in solution

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