Site-specific labelling of native peptides and proteins: chemical and enzymatic strategies

• Antonio Angelastro,
• Jonathan Bargh,
• Subhajit Guria,
• Victor Laserna and
• Louis Luk

Beilstein J. Org. Chem. 2026, 22, 857–881, doi:10.3762/bjoc.22.67

• (1), b) reductive amination by sodium cyanoborohydride, c) native chemical ligation, d) cysteine-reactive 2-cyanobenzothiazole 2 and e) formylphenylboronic acid 3 (FPBA) reacting with N-terminal cysteine. Introduction of carbonyl functionality at protein N-termini via a) oxidation by periodate, b

Economical and scalable synthesis of 6-amino-2-cyanobenzothiazole

• Jacob R. Hauser,
• Hester A. Beard,
• Mary E. Bayana,
• Katherine E. Jolley,
• Stuart L. Warriner and
• Robin S. Bon

Beilstein J. Org. Chem. 2016, 12, 2019–2025, doi:10.3762/bjoc.12.189

• preparation of luciferins 3 involves straightforward condensation of CBTs 1 with D-cysteine (2) (Scheme 1). For BLI applications, luciferins are often generated in vivo from CBTs [4][5][6][7], which are easier to modify and handle due to their higher stability, cell permeability, and reactivity than the full

Cyclisation mechanisms in the biosynthesis of ribosomally synthesised and post-translationally modified peptides

• Andrew W. Truman

Beilstein J. Org. Chem. 2016, 12, 1250–1268, doi:10.3762/bjoc.12.120

• aminovinylcysteine [62] (AviCys, Figure 5A). This is found in a variety of RiPPs that also feature conventional lanthionine rings, such as epidermin [63] (Figure 5A), mersacidin [64] and cypemycin [65]. In epidermin, a S-[(Z)-2-aminovinyl]-D-cysteine (AviCys) residue is formed by the 1,4-nucleophilic addition of an

• biosynthesis of labyrinthopeptin A2. S-[(Z)-2-Aminovinyl]-D-cysteine (AviCys) formation in the epidermin pathway. A) Mechanisms for decarboxylation and 1,4-addition. B) Mechanism for the E. coli Dfp-catalysed conversion of (R)-4'-phospho-N-pantothenoylcysteine into 4'-phosphopantetheine during coenzyme A

Development of peptidomimetic ligands of Pro-Leu-Gly-NH₂ as allosteric modulators of the dopamine D₂ receptor

• Swapna Bhagwanth,
• Ram K. Mishra and
• Rodney L. Johnson

Beilstein J. Org. Chem. 2013, 9, 204–214, doi:10.3762/bjoc.9.24

• accomplished through the condensation of α-alkylaldehyde proline derivatives 34a–c with either D-cysteine or D-homocysteine derivatives to give diastereoisomeric mixtures of thiazolidines 35, 37 and 38 and thiazines 36, respectively (Scheme 2). Formation of the lactam ring from the thiazine and thiazolidines

Ratiometric fluorescent probe for enantioselective detection of D-cysteine in aqueous solution

• Xiao-bo Zhou,
• Wing-Hong Chan,
• Albert W. M. Lee and
• Chi-Chung Yeung

Beilstein J. Org. Chem. 2011, 7, 1508–1515, doi:10.3762/bjoc.7.176

• enantioselective detection of cysteine in 99:1 buffered HEPES:ACN solutions. Under the measuring conditions, the sensor demonstrates high selectivity toward Cys against Hcy and GSH, and an enantioselectivity of 3.35 can be achieved for antipodal forms of Cys. Keywords: chemosensor; D-cysteine; enantioselectivity

• enantioselectivity of 3.35 conferred by the chiral trans-1,2-diaminocyclohexane moiety for recognizing D-cysteine in 1% ACN/HEPES buffered solutions (pH 7.4) (Figure 5). Apparently, owing to the structure complementarity of the host–guest, D-cysteine outperforms its enantiomer in forming a more stable complex with