Selective and reversible photochemical derivatization of cysteine residues in peptides and proteins

Abstract

Selective derivatization of solvent-exposed cysteine residues in peptides and proteins is achieved by brief irradiation of an aqueous solution containing 3-(hydroxymethyl)-2-naphthol derivatives (NQMPs) with 350 nm fluorescent lamp. NQMP can be conjugated with various moieties, such as PEG, dyes, carbohydrates, or possess a fragment for further selective derivatization, e.g., biotin, azide, alkyne, etc. Attractive features of this labeling approach include an exceptionally fast rate of the reaction and a requirement for low equivalence of the reagent. The NQMP-thioether linkage is stable under ambient conditions, survives protein digestion and MS analysis. Irradiation of NQMP-labeled protein in a dilute solution (<40 μM) or in the presence of a vinyl ether results in a traceless release of the substrate. The reversible biotinylation of bovine serum albumin, as well as capture and release of this protein using NeutrAvidin Agarose resin beads has been demonstrated.

Kinon-metidi (II. dio): Fotokemijsko generiranje i razvoj primjene u fotokemoterapiji

“…46,47,85 Također je pokazano da se QM mogu upotrijebiti i za obilježavanje proteina u svrhu istraživanja protein-ligand ili protein-protein interakcija. 68,86 Veoma dobro je istražena reaktivnost fotogeneriranih QM-a s nukleinskim kiselinama. QM može alkilirati nukleinsku kiselinu na fosfatnoj okosnici i na samoj nukleobazi.…”

Photo-Triggered Click Chemistry for Biological Applications

“…However, the adduct was photochemically labile; upon longer irradiation time (30 min instead of 20 min) it was converted back to NQMP 79 ) (Scheme 14). The feature that oNQMs react faster with thiols (in reversible way) but slower than vinyl ethers (in irreversible way) was exploited in the controlled release of thiol functionalized compounds o NQMs (Scheme 15) [80]. First, with a short irradiation (2–5 min, 300 or 350 nm) the thiol adduct ( 92 ) was formed, which was later released quantitatively with 2–5 min (350 nm) irradiation in the presence of ethyl vinyl ether.…”

Photo-Triggered Click Chemistry for Biological Applications

“…The enamines (86) are another class of electron-rich polarized alkenes which could undergo facile cycloaddition reaction with oNQMs (80), but the primary cycloadducts (88) rapidly hydrolyze in aqueous medium to produce 2-hydroxybenzochromanes (90). Nevertheless, this method is suitable for the introduction of functional groups at position 3 of the benzochromane (90) (Scheme 14).…”

“…However, the adduct was photochemically labile; upon longer irradiation time (30 min instead of 20 min) it was converted back to NQMP 79) (Scheme 14). The feature that oNQMs react faster with thiols (in reversible way) but slower than vinyl ethers (in irreversible way) was exploited in the controlled release of thiol functionalized compounds oNQMs (Scheme 15) [80]. First, with a short irradiation (2-5 min, 300 or 350 nm) the thiol adduct (92) was formed, which was later released quantitatively with 2-5 min (350 nm) irradiation in the presence of ethyl vinyl ether.…”

“…Reactive oNQMs (80) can also be efficiently captured by strong nucleophiles such as thiols presented in millimolar concentrations in biological systems. They observed thiol addition (k 2 = 2.2 × 10 5 M −1 s −1 with thioethanolamine; 5-times faster than the DA reaction with ethyl vinyl ether).…”