25691-37-6Relevant articles and documents
An Improved Preparation of N2-tert-Butoxycarbonyl- and N 2-Benzyloxycarbonyl-(S)-2,4-diaminobutanoic Acids
Andruszkiewicz, Ryszard,Rozkiewicz, Dorota
, p. 1049 - 1056 (2004)
Utilizing N-benzyloxycarbonyl- (1a) and N-tert-butoxycarbonyl-(S) -glutamine (1b), a highly efficient and practical method for the synthesis of N2-benzyloxycarbonyl- and N 2-tert-butoxycarbonyl-(S)-2,4-diamino-butanoic acids (2a and 2b) has been developed. Reaction of (S)-glutamine derivatives with iodosobenzene diacetate in a mixture of THF-water at 4°C afforded selectively protected (S)-2,4-diaminobutanoic acids in good yields.
The microenvironment and pKaperturbation of aminoacyl-tRNA guided the selection of cationic amino acids
Hazra, Bibhas,Prasad, Mahesh,Roy, Rajat,Tarafdar, Pradip K.
supporting information, p. 8049 - 8056 (2021/10/04)
The proteinogenic lysine (Lys) and arginine (Arg) have multiple methylene groups between α-carbon and the terminal charged centre. Why nature did not select ornithine (Orn), 2,4-diamino butyric acid (Dab) and 2,3-diamino propionic acid (Dpr) with fewer methylene groups in the side chain remains an important question! The propensity of aminoacyl-tRNA (aa-tRNA) model substrates towards self-degradationviaintramolecular lactamization was studied using UV spectroscopy and1H-NMR titration, which showed that Lys and Arg remain stable, and Orn and Dab cyclize to lactam. Hydrophobicity-assisted surface mediated model peptide formation highlighted that the microenvironment and pKaperturbation led to poor regioselectivity (α-aminevs.terminal amine) in Dpr and other non-proteinogenic analogues. The α-selectivity became even poorer in the presence of phosphate, making them ill-suited for peptide synthesis. Superior regioselectivity of the Lys aa-tRNA model substrate suggests that the extra methylene bridge helped nature to separate the microenvironments of the α-amine and ε-amine to synthesize the peptide backbone.
Cγ(S/ R)-Bimodal Peptide Nucleic Acids (Cγ- bm-PNA) Form Coupled Double Duplexes by Synchronous Binding to Two Complementary DNA Strands
Bhingardeve, Pramod,Madhanagopal, Bharath Raj,Ganesh, Krishna N.
supporting information, p. 13680 - 13693 (2020/12/15)
Peptide nucleic acids (PNAs) are linear equivalents of DNA with a neutral acyclic polyamide backbone that has nucleobases attached via tert-amide link on repeating units of aminoethylglycine. They bind complementary DNA or RNA with sequence specificity to form hybrids that are more stable than the corresponding DNA/RNA self-duplexes. A new type of PNA termed bimodal PNA [Cγ(S/R)-bm-PNA] is designed to have a second nucleobase attached via amide spacer to a side chain at Cγon the repeating aeg units of PNA oligomer. Cγ-bimodal PNA oligomers that have two nucleobases per aeg unit are demonstrated to concurrently bind two different complementary DNAs, to form duplexes from both tert-amide side and Cγside. In such PNA:DNA ternary complexes, the two duplexes share a common PNA backbone. The ternary DNA 1:Cγ(S/R)-bm-PNA:DNA 2 complexes exhibit better thermal stability than the isolated duplexes, and the Cγ(S)-bm-PNA duplexes are more stable than Cγ(R)-bm-PNA duplexes. Bimodal PNAs are first examples of PNA analogues that can form DNA2:PNA:DNA1 double duplexes via recognition through natural bases. The conjoined duplexes of Cγ-bimodal PNAs can be used to generate novel higher-level assemblies.
