- Design of peptides with α,β-dehydro residues: A dipeptide with a branched β-carbon dehydro residue at the (i+1) position, methyl N-(benzyloxycarbonyl)-α, β-didehydrovalyl-l-tryptophanate
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The structure of the title peptide, C25H27N3O5, has been determined and its conformation analysed. Values of the standard peptide torsion angles are Φ1 = -44.2 (3)°, Ψ1 = 135.9 (2)°, Φ
- Vijayaraghavan,Kumar,Dey,Singh
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- Design of peptides with α, β-dehydro-residues: Synthesis and crystal structure of a tripeptide N-benzyloxycarbonyl-ΔVal-ΔPhe-L- Ala-OCH3
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In order to develop the design rules for producing specific conformations of peptides with α, β-dehydro-residues a peptide Cbz-ΔVal- ΔPhe-Ala-OCH3 was synthesized in solution phase. The crystal structure has been determined by X-ray diffraction method. The structure was refined to an R-value of 0.050. The peptide adopts a type I β-turn conformation with backbone torsion angles of two corner residues, φ1=-53.9(6)°, ψ1=-33.0(6)°, φ2=-73.7(5)°and ψ2=-12.2(6)°. The conformation is stabilized by an intramolecular 4→1 hydrogen bond involving NH of Ala residue as a donor and carbonyl oxygen atom of Cbz group as an acceptor. The torsion angles, χ11,1=172.8(6) and χ11,2=-6.9(9) of ΔVal residue indicate that its side chain is planar while the torsion angles, χ2 1=-9.0(9), χ22,1=-43.4(10) and χ22,2=130.1(9) show that the side chain of ΔPhe deviates considerably from the planarity. This is the first sequence in which ΔVal and ΔPhe are introduced at adjacent positions and the structure reveals clearly that the side chain of ΔPhe is a relatively less rigid than that of ΔVal. The molecules are packed in columns parallel to c-axis.
- Goel, Vijay Kumar,Dey, Sharmistha,Singh, Tej P.
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- Impact of Dehydroamino Acids on the Structure and Stability of Incipient 310-Helical Peptides
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A comparative study of the impact of small, medium-sized, and bulky α,β-dehydroamino acids (AAs) on the structure and stability of Balaram's incipient 310-helical peptide (1) is reported. Replacement of the N-terminal Aib residue of 1 with a AA
- Joaquin, Daniel,Lee, Michael A.,Kastner, David W.,Singh, Jatinder,Morrill, Shardon T.,Damstedt, Gracie,Castle, Steven L.
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p. 1601 - 1613
(2019/12/02)
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- Asymmetric hydrogenation of N-sulfonylated-α-dehydroamino acids: Toward the synthesis of an anthrax lethal factor inhibitor
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(Chemical Equation Presented) A novel and highly enantioselective Ru-catalyzed hydrogenation of N-sulfonylated-α-dehydroamino acids has been discovered and demonstrated in the synthesis of an anthrax lethal factor inhibitor (LFI). Herein, this methodology is used to prepare N-sulfonylated amino acids in up to 98% ee. This unprecedented hydrogenation uses a chiral Ru catalyst rather than Rh as typical for acylated dehydroamino acids and esters, and this work reports the first asymmetric hydrogenation of a tetrasubstituted dehydroamino acid derivative using a Ru catalyst.
- Shultz, C. Scott,Dreher, Spencer D.,Ikemoto, Norihiro,Williams, J. Michael,Grabowski, Edward J. J.,Krska, Shane W.,Sun, Yongkui,Dormer, Peter G.,DiMichele, Lisa
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p. 3405 - 3408
(2007/10/03)
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- Design of peptides with α,β-dehydro-residues: Synthesis, crystal structure and molecular conformation of a tetrapeptide Z-ΔVal-Val-ΔPhe-Ile-Ome
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This is the first designed peptide with a combination of a branched β-carbon ΔVal and a ΔPhe residues. The peptide Z-ΔVal-Val-ΔPhe-Ile-Ome was synthesized in solution phase. Single crystals were grown by slow evaporation from its solution in acetone-water
- Makker,Dey,Mukherjee,Vijayaraghavan,Kumar,Singh
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p. 119 - 124
(2007/10/03)
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