Molecular and crystal structure of a terminally-blocked Aib homotetrapeptide *
Abstract
The molecular and crystal structure of an acetonitrile solvate of the synthetic, terminally-blocked homo-tetrapeptide from α-aminoisobutyric acid [Ac – (Aib)4 – OtBu] (1) was determined by single-crystal X-ray diffraction. The compound possesses the following parameters: triclinic, space group P[unk] (No. 2), a = 17.751(2) Å, b = 9.999(2) Å, c = 9.327(2) Å, α = 113.0(1)°, β = 85.6(1)°, γ = 105.0(1)°, and Z = 2. The crystal structure was solved by direct methods. The least-squares refinement led to R and Rw values of 0.059 and 0.061, respectively, for 3472 reflections with I [unk] 3σ(I). The tetrapeptide is folded into two consecutive type-III (III′) β-bend conformations (incipient 310-helix), stabilized by two intramolecular N – H … O = C H-bonds. A short contact is observed between the nitrogen atom of the acetonitrile molecule and the Aib2 NH group.
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Articles in the same Issue
- Crystal structure of a cholesterogen – cholesteryl methyl carbonate (CMC)
- An X-ray search for anharmonicity in indium phosphide
- Crystal structure and spectra of bis[p-chloro-benzoyl-di-(2-pyridyl)ketonohydrazono]uranyl
- Crystal structures of isomorphous triaquatris(3-aminobenzoato-O, O)yttrium(III) trihydrate and triaquatris(3-aminobenzoato-0,0)lanthanide(III) trihydrate
- Crystal structure of calcium hydroxide nitrate hydrate and its superstructure in relation to cadmium hydroxide nitrate hydrate
- Structural phase transition in GaMo4Se8 and AlMo4S8 by X-ray powder diffraction
- The crystal structure of Ce4Ru3
- Allowance for Debye scattering in Wilson-plot least-squares procedures
- The (1:1) adducts of (2,4-dichlorophenoxy)acetic acid with 4-aminobenzoic acid and triphenylphosphine oxide *
- Molecular and crystal structure of a terminally-blocked Aib homotetrapeptide *
- Molecular and crystal structure of Nα-benzyloxycarbonyl-l-proline amide *
- Schwingungsspektroskopische Untersuchungen an SiO2-Clathraten
- Liebauite, Ca3Cu5Si9O26: A new silicate mineral with 14er single chain
- The crystal and molecular structure of tramazoline hydrochloride monohydrate, C13H18N3+Cl−·H2O
- Crystal structure of sphagnum acid, C11H10O5
- High resolution X-ray investigations on the supersatellite reflections of Labradorite
- The crystal structure of di(5-amino-3-thione-l,2,4-dithiazole)-tris-thiocyanatobismuthate (III), (C2H2N2S3)2Bi(SCN)3 determined at 100 K
- The structure type of ludwigite
