Structural Characterization of a Gcn5-Related N-Acetyltransferase from Staphylococcus aureus

Abstract

The Gcn5-related N-acetyltransferases (GNATs) are ubiquitously expressed in nature and perform a diverse range of cellular functions through the acetylation of small molecules and protein substrates. Using activated acetyl coenzyme A as a common acetyl donor, GNATs catalyse the transfer of an acetyl group to acceptor molecules including aminoglycoside antibiotics, glucosamine-6-phosphate, histones, serotonin and spermidine. There is often only very limited sequence conservation between members of the GNAT superfamily, in part, reflecting their capacity to bind a diverse array of substrates. In contrast, the secondary and tertiary structures are highly conserved, but then at the quaternary level there is further diversity, with GNATs shown to exist in monomeric, dimeric, or tetrameric states. Here we describe the X-ray crystallographic structure of a GNAT enzyme from Staphyloccocus aureus with only low sequence identity to previously solved GNAT proteins. It contains many of the classical GNAT motifs, but lacks other hallmarks of the GNAT fold including the classic β-bulge splayed at the β-sheet interface. The protein is likely to be a dimer in solution based on analysis of the asymmetric unit within the crystal structure, homology with related GNAT family members, and size exclusion chromatography. The study provides the first high resolution structure of this enzyme, providing a strong platform for substrate and cofactor modelling, and structural/functional comparisons within this diverse enzyme superfamily.

Discovery and reduction of nonspecific activities of the major herbicide-resistance gene BAR

“…Our refined structures revealed that BAR is an αβ protein harboring a globular tertiary structure resembling the previously reported Gcn5-related N-acetyltransferase (GNAT) structures ( Supplementary Fig. 5) [16][17][18][19] . BAR crystalizes as a homodimer with two active sites symmetrically distributed around the dimer interface inside a large open cavity ( Fig.…”

Epigenetics in ovarian cancer: premise, properties, and perspectives

“…The GNAT enzyme superfamily is widespread in nature [ 26 ]. In spite of substrate diversity, GNAT superfamily members are generally characterized by a highly conserved GNAT domain (composed of 6–7 anti-parallel β-strands and 4 α-helices in the topology β1-α1-α2-β2-β3-β4-α3-β5-α4-β6-β7 [ 26 , 27 ]), and can acetylate lysine residues on histones H2B, H3, and H4. GNAT domain contains three conserved motifs in the order of D-A-B.…”

“…Motifs D preserves the stable state of these proteins. Some other members of GNAT family harbor another conserved motifs C that is located at the N-terminus of these proteins [ 27 , 28 ]. Although the structure of p300/CBP family has not yet been fully elucidated, several studies have shown that the structure and the catalytic mechanism of this group of proteins are obviously distinct from the MYST and GNAT families [ 29 ].…”

“…Biochemical purifications reveal hMOF forms two distinct multicomplexes in mammalian cells: MSL (Male Specific Lethal)-associated MOF and NSL (Non-Specific Lethal)-associated MOF [ 34 ]. MSL-associated MOF exhibits strong specificity for histone H4K16 [ 27 , 35 ]. NSL-MOF exhibits relaxed substrate specificity [ 36 ], and acetylates histone H4 at K5, 8, and 16 [ 27 , 34 , 37 , 38 ].…”

“…MSL-associated MOF exhibits strong specificity for histone H4K16 [ 27 , 35 ]. NSL-MOF exhibits relaxed substrate specificity [ 36 ], and acetylates histone H4 at K5, 8, and 16 [ 27 , 34 , 37 , 38 ]. Depletion of hMOF reduces histone H4K16 acetylation, gene instability, and cell cycle disorder.…”