Live‐Cell Studies of p300/CBP Histone Acetyltransferase Activity and Inhibition

Histone acetyltransferase enzymes (HATs) are important therapeutic targets, but there are few cell‐based assays available for evaluating the pharmacodynamics of HAT inhibitors. Here we present the application of a FRET‐based reporter, Histac, in live‐cell studies of p300/CBP HAT inhibition, by both genetic and pharmacologic disruption. shRNA knockdown of p300/CBP led to increased Histac FRET, thus suggesting a role for p300/CBP in the acetylation of the histone H4 tail. Additionally, we describe a new p300/CBP HAT inhibitor, C107, and show that it can also increase cellular Histac FRET. Taken together, these studies provide a live‐cell strategy for identifying and evaluating p300/CBP inhibitors.     

Cover Picture: Selective Protein Degradation by Ligand‐Targeted Enzymes: Towards the Creation of Catalytic Antagonists (ChemBioChem 6/2003)

The cover picture shows a ligand‐targeted proteinase enzyme or “catalytic antagonist” acting as a molecular angler fish: By precisely positioning different binding ligands (L) around the active site “mouth” of a degradative proteinase enzyme, target proteins (TP) can be plucked from solution, locked in position adjacent to the catalytic triad “jaws”, and in this way readily and specifically degraded. The hunting strategy of the deep sea angler fish, which uses a lure above its mouth, illustrates this principle. Further details can be found in the article by B. Davis, R. R. Bott, J. B. Jones et. al. on pp. 533–537.     

Cover Picture: Semisynthesis and Characterization of the First Analogues of Pro‐Neuropeptide Y (ChemBioChem 5/2003)

The cover picture shows how a combination of recombinant synthesis and chemical synthesis has been used to obtain chemically modified proteins. N‐terminal protein segments of pro‐neuropeptide Y (proNPY) were produced as intein‐fusion proteins in Escherischia coli in order to obtain thioesters. C‐terminal segments were synthesized by parallel automated peptide synthesis and derivatized to obtain carboxyfluorescein‐ (CF) and biotin‐labeled peptides. Native chemical ligation yielded chemically modified full‐length analogues of proNPY that can be used to monitor the biosynthesis of neuropeptide Y. Futher information can be found in the article by Beck‐Sickinger and co‐workers on p. 425 ff.