- Substrate derived peptidic α-ketoamides as inhibitors of the malarial protease PfSUB1
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Peptidic α-ketoamides have been developed as inhibitors of the malarial protease PfSUB1. The design of inhibitors was based on the best known endogenous PfSUB1 substrate sequence, leading to compounds with low micromolar to submicromolar inhibitory activity. SAR studies were performed indicating the requirement of an aspartate mimicking the P1′ substituent and optimal P1-P4length of the non-prime part. The importance of each of the P1-P4amino acid side chains was investigated, revealing crucial interactions and size limitations.
- Kher, Samir S.,Penzo, Maria,Fulle, Simone,Finn, Paul W.,Blackman, Michael J.,Jirgensons, Aigars
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supporting information
p. 4486 - 4489
(2015/02/19)
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- Efficient access to enantiopure γ4-amino acids with proteinogenic side-chains and structural investigation of γ4- asn and γ4-ser in hybrid peptide helices
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Hybrid peptides composed of α- and β-amino acids have recently emerged as new class of peptide foldamers. Comparatively, γ- and hybrid γ-peptides composed of γ4-amino acids are less studied than their β-counterparts. However, recent investigations reveal that γ4-amino acids have a higher propensity to fold into ordered helical structures. As amino acid side-chain functional groups play a crucial role in the biological context, the objective of this study was to investigate efficient synthesis of γ4-residues with functional proteinogenic side-chains and their structural analysis in hybrid-peptide sequences. Here, the efficient and enantiopure synthesis of various N- and C-terminal free-γ4-residues, starting from the benzyl esters (COOBzl) of N-Cbz-protected (E)-α,β-unsaturated γ-amino acids through multiple hydrogenolysis and double-bond reduction in a single-pot catalytic hydrogenation is reported. The crystal conformations of eight unprotected γ4-amino acids (γ4-Val, γ4-Leu, γ4-Ile, γ4-Thr(OtBu), γ4-Tyr, γ4-Asp(OtBu), γ4- Glu(OtBu), and γ-Aib) reveals that these amino acids adopted a helix favoring gauche conformations along the central Cγi£ Cβ bond. To study the behavior of γ4- residues with functional side chains in peptide sequences, two short hybrid γ-peptides P1 (Ac-Aib-γ4-Asn-Aib-γ4-Leu- Aib-γ4-Leu-CONH2) and P2 (Ac-Aib- γ4-Ser-Aib-γ4-Val-Aib-γ4-Val- CONH2) were designed, synthesized on solid phase, and their 12-helical conformation in single crystals were studied. Remarkably, the γ4-Asn residue in P1 facilitates the tetrameric helical aggregations through interhelical H bonding between the side-chain amide groups. Furthermore, the hydroxyl side-chain of γ4-Ser in P2 is involved in the interhelical H bonding with the backbone amide group. In addition, the analysis of 87 γ4-residues in peptide single-crystals reveal that the γ4-residues in 12-helices are more ordered as compared with the 10/12- and 12/14-helices. Copyright
- Jadhav, Sandip V.,Misra, Rajkumar,Singh, Sumeet K.,Gopi, Hosahudya N.
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p. 16256 - 16262
(2013/12/04)
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- Peptide fragment coupling using a continuous-flow photochemical rearrangement of nitrones
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Go with the flow: A general approach for amide bond formation by way of a continuous-flow photochemical rearrangement of nitrones was described (see scheme). Simple aryl-alkyl amide bonds as well as complex peptide bonds were constructed efficiently with a residence time less than 20minutes. A tetrapeptide was synthesized in this way and the method could be applied to peptide fragment coupling. Copyright
- Zhang, Yuan,Blackman, Melissa L.,Leduc, Andrew B.,Jamison, Timothy F.
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supporting information
p. 4251 - 4255
(2013/05/08)
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- Synthesis of threo-β-aminoalcohols from aminoaldehydes via chelation-controlled additions. Total synthesis of l-threo sphingosine and safingol
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Chelation-controlled addition of organocuprates to N-carbamoyl aminoaldehydes, prepared from functionalized amino acids, generated predominately the threo-β-amino alcohol derivatives through chelation with the carbamoyl moiety. The carbamate group is a stronger chelating group than other potentially good chelators, for example ethers, esters, thioethers, and gives good diastereoselectivity with cuprates. Thus addition of lithium divinylcuprate to the aldehyde generated from the serine derivative 25 in the presence of extra copper for chelation afforded the threo compound 26 in 83% yield. Cross-metathesis and cleavage of the protecting groups furnished l-threo sphingosine 21. In addition the lyso-sphingolipid protein kinase C inhibitor, safingol, 22, was prepared from commercially available O-benzyl N-BOC serine 28 in six steps and 56% overall yield by this method.
- Jung, Michael E.,Yi, Sung Wook
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p. 4216 - 4220
(2012/08/29)
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