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Insights on HIV‐1 Tat:P/CAF bromodomain molecular recognition from in vivo experiments and molecular dynamics simulations
Author(s) -
Pantano Sergio,
Marcello Alessandro,
Ferrari Aldo,
Gaudiosi Daniele,
Sabò Arianna,
Pellegrini Vittorio,
Beltram Fabio,
Giacca Mauro,
Carloni Paolo
Publication year - 2005
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.20805
Subject(s) - bromodomain , transactivation , acetylation , chemistry , förster resonance energy transfer , in vivo , molecular dynamics , biophysics , biochemistry , molecular model , microbiology and biotechnology , biology , fluorescence , transcription factor , gene , genetics , physics , computational chemistry , quantum mechanics
Structural and functional studies indicate that, through its bromodomain, the cellular acetyltransferase P/CAF binds the acetylated Tat protein of human immunodeficiency virus type 1 (HIV‐1) and promotes transcriptional activation of the integrated provirus. Based on the NMR structure of P/CAF complexed with an acetylated Tat peptide, here we use molecular dynamics simulations to construct a model describing the interaction between full length Tat and the P/CAF bromodomain. Our calculations show that the protein–protein interface involves hydrophobic interactions between the P/CAF ZA loop and the Tat core domain. In particular, tyrosines 760 and 761 of P/CAF, two residues that are highly conserved in most known bromodomains, play an essential role for the binding. Fluorescence resonance energy transfer (FRET) experiments performed in this work demonstrate that P/CAF proteins in which these tyrosines are mutated into hydrophilic residues neither bind to Tat inside the cells nor mediate Tat transactivation. The combination of theoretical and in vivo studies provides new insights into the specificity of bromodomain recognition. Proteins 2006. © 2005 Wiley‐Liss, Inc.