PMC

Rhoda‐electrocatalyzed C−H ethylation of N‐heterocycles.

Rhoda‐electrocatalyzed C−H ethylation of 2‐phenylpyridines.

Iron-catalyzed triazole assisted ethylation of C(sp²)–H bond. (a) Ethylation of TAM amides 1; (b) Ethylation of TST amide 10f; (c) Ethylation of ferrocene amide 6a; (d) Triazole removal protocol.

MALDI‐TOF MS assays showing methylation (top) and ethylation reactions (middle and bottom) of A) H3Orn9 by G9a and B) H3Orn9 by GLP.

MALDI‐TOF MS assays showing methylation (top) and ethylation reactions (middle and bottom) of A) H3K9me by G9a, B) H3K9me by GLP, C) H3K9me2 by G9a, and D) H3K9me2 by GLP.

MALDI‐TOF MS assays showing methylation (top) and ethylation reactions (middle and bottom) of A) H3K4 by SETD7, B) H4K20 by SETD8, C) H3K9 by G9a, and D) H3K9 by GLP.

Histone 3 lysine ethylation is a novel posttranslational modification. A, B) Representative MS/MS spectra and ion tables of the unmodified (A) and the ethylated (B) peptide KSAPATGGVKKPHR. B₁₀-b₁₃ ions and y₅-y₁₃ ions demonstrate the ethylation of K10 (+33 Da). C) N-terminal sequence of histone 3. Black letters mark peptides with identified lysine ethylation and red Ks mark the localization of the modified lysines. Lower panels: Quantitation of peptides containing ethionine-d₅. Histone 3 peptides were from THP-1 cells grown in the presence of 2.5 mM ethionine or ethionine-d₅ for 48 h.

KMT‐catalyzed alkylation of histones. A) AdoMet‐mediated lysine methylation, leading to Kme, Kme2, and Kme3. B) View from a crystal structure of G9a‐like protein (GLP; green) in complex with H3K9me (violet) and S‐adenosylhomocysteine (AdoHcy; yellow; PDB ID: 3HNA). C) S‐Adenosylethionine (AdoEth)‐ or Se‐adenosylselenoethionine (AdoSeEth)‐mediated lysine ethylation, leading to Ket.

Methylation and ethylation interference analyses of vnd/NK-2 HD binding to the N2 site of the 5′-flanking sequence of vnd/NK-2 genomic DNA. (A) Autoradiograph of a methylation interference analysis. Symbols are the same as described in . (B) Image analysis of an autoradiograph of methylation interference assays. Symbols are the same as described in . (C) Autoradiograph of an ethylation interference analysis of the 5′-flanking sequence of vnd/NK-2 genomic DNA. The vertical bar represents the region of DNase I footprinting sites (N2 and N2′) from . Other symbols are the same as described in . (D) Image analysis of an autoradiograph of an ethylation interference assay. (E) Summary of methylation and ethylation interference results. The box indicates the consensus sequence for vnd/NK-2 HD binding. Circles represent methylated residues that interfere with vnd/NK-2 HD binding in B₁. Other symbols are the same as described in .

Ethylation interference footprinting of RepA-DNA complexes. Lane a, G+A Maxam-Gilbert sequencing markers; lane b, ethylated DNA not subjected to RepA binding; lanes c and d, unbound and bound fractions, respectively, of ethylated DNA subjected to RepA binding. Partially resolved multiple bands can usually be seen due to alternative ethylations at the two oxygens of each phosphate and occasional ethylation of the bases. The numbers indicate base positions related to interference with RepA binding. Bands marked with arrows indicate that interference at position −5 on the top strand and position 6 on the bottom strand was due to ethylation of the bases. Ethylation of phosphates 3′ to the base at position 2 on the top strand and 3′ to the bases at positions −3, 7, 8, and 9 on the bottom strand interfered with RepA binding. The locations of these phosphates can be seen on B-form DNA in Fig. .

Cross-coupling ethylation of 1,5-naphthyridine.

Ethylation and hydrolysis of N-acetylaminopyridines.

Additional substrate scope of directed ruthenium-catalyzed C–H ethylation reactions. DG=directing group, Py=pyridyl.

(A) Introduction of an azetidin-3-yl group. (B) Ethylation of camptothecin.

Ethylation of diazinone 5 at the 2 and 4-positions.

Ruthenium-catalyzed C_sp³–H ethylation reactions and their dependence on directing group functionality.

Ethylation of 3-isopropyloxindole (8f) under insufficiently inert conditions.

Reproduced with permission from Biochemistry (2008) 46, 14682–92.