Probing the reaction coordinate of the p300/CBP histone acetyltransferase with bisubstrate analogs

Department of Pharmacology and Molecular Sciences, Johns Hopkins Medical Institute, 725 N. Wolfe Street, Baltimore, MD 21205, USA.
Bioorganic Chemistry (Impact Factor: 2.14). 02/2011; 39(1):42-7. DOI: 10.1016/j.bioorg.2010.10.004
Source: PubMed

ABSTRACT Histone and protein acetylation catalyzed by p300/CBP transcriptional coactivator regulates a variety of key biological pathways. This study investigates the proposed Theorell-Chance or "hit-and-run" catalytic mechanism of p300/CBP histone acetyltransferase (HAT) using bisubstrate analogs. A range of histone peptide tail peptide-CoA conjugates with different length linkers were synthesized and evaluated as inhibitors of p300 HAT. We show that longer linkers between the histone tail peptide and the CoA substrate moieties appear to allow for dual engagement of the two binding surfaces. Results with D1625R/D1628R double mutant p300 HAT further confirm the requirement for a negatively charged surface on the enzyme to interact with the histone tail.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Three decades of research into p300/CBP, since the first report in 1985, have revealed its importance to normal cell health and etiology of disease. p300/CBP is a key enzyme in higher eukaryotes, where it acts as an effector in myriad major cellular signaling pathways, which modulate protein functions and gene expression in response to a variety of signals. This is accomplished by binding of over 400 protein ligands to its various protein interaction-mediating domains and the acetylation of ∼100 protein substrates. The unusual hit-and-run kinetic mechanism has permitted the identification of p300/CBP-specific acetyltransferase inhibitors, which have shown promising effects in studies in living cells. The protein acetylation and protein binding functions of p300/CBP are intricately interrelated, and both are targets of pharmacological interventions that may have considerable therapeutic applications.
    Chemical Reviews 01/2015; DOI:10.1021/cr500452k · 45.66 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The transcriptional coactivator and histone acetyltransferase (HAT) p300 acetylates the four core histones and other transcription factors to regulate a plethora of fundamental biological processes including cell growth, development, oncogenesis and apoptosis. Recent structural and biochemical studies on the p300 HAT domain revealed a Theorell-Chance, or "hit-and-run", catalytic mechanism. Nonetheless, the chemical mechanism of the entire reaction process including the proton transfer (PT) scheme and consequent acetylation reaction route still remains unclear. In this study, a combined computational strategy consisting of molecular modeling, molecular dynamic (MD) simulation and quantum mechanics/molecular mechanics (QM/MM) simulation was applied to elucidate these important issues. An initial p300/H3/Ac-CoA complex structure was modeled and optimized using a 100 ns MD simulation. Residues that play important roles in substrate binding and the acetylation reaction were comprehensively investigated. For the first time, these studies reveal a plausible PT scheme consisting of Y1394, D1507 and a conserved crystallographic water molecule, with all components of the scheme being stable during the MD simulation and the energy barrier low for proton transfer to occur. The two-dimensional potential energy surface for the nucleophilic attack process was also calculated. The comparison of potential energies for two possible elimination half-reaction mechanisms revealed that Y1467 reprotonates the coenzyme-A leaving group to form product. This study provides new insights into the detailed catalytic mechanism of p300 and has important implications for the discovery of novel small molecule regulators for p300.
    The Journal of Physical Chemistry B 02/2014; 118(8). DOI:10.1021/jp409778e · 3.38 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Long known for their role in histone acetylation, recent studies have demonstrated that lysine acetyltransferases also carry out distinct "orphan" functions. These activities impact a wide range of biological phenomena including metabolism, RNA modification, nuclear morphology, and mitochondrial function. Here, we review the discovery and characterization of orphan lysine acetyltransferase functions. In addition to highlighting the evidence and biological role for these functions in human disease, we discuss the part emerging chemical tools may play in investigating this versatile enzyme superfamily.
    ACS Chemical Biology 01/2015; 10(1):85-94. DOI:10.1021/cb500853p · 5.36 Impact Factor


Available from