Structural characterization of a GNAT family acetyltransferase from Elizabethkingia anophelis bound to acetyl-CoA reveals a new dimeric interface

Abstract

General control non-repressible 5 (GCN5)-related N-acetyltransferases (GNATs) catalyse the acetylation of a diverse range of substrates, thereby orchestrating a variety of biological processes within prokaryotes and eukaryotes. GNAT enzymes can catalyze the transfer of an acetyl group from acetyl coenzyme A to substrates such as aminoglycoside antibiotics, amino acids, polyamines, peptides, vitamins, catecholamines, and large macromolecules including proteins. Although GNATs generally exhibit low to moderate sequence identity, they share a conserved catalytic fold and conserved structural motifs. In this current study we characterize the high-resolution X-ray crystallographic structure of a GNAT enzyme bound with acetyl-CoA from Elizabethkingia anophelis, an important multi-drug resistant bacterium. The tertiary structure is comprised of six α-helices and nine β-strands, and is similar with other GNATs. We identify a new and uncharacterized GNAT dimer interface, which is conserved in at least two other unpublished GNAT structures. This suggests that GNAT enzymes can form at least five different types of dimers, in addition to a range of other oligomers including trimer, tetramer, hexamer, and dodecamer assemblies. The high-resolution structure presented in this study is suitable for future in-silico docking and structure–activity relationship studies.

Genetic variation in symbiotic islands of natural variant strains of soybean Bradyrhizobium japonicum and Bradyrhizobium diazoefficiens differing in competitiveness and in the efficiency of nitrogen fixation

“…The SNP in strain S 340 at the position 8264276 bp resulted in the exchange of the amino acid arginine in the RimL domain by the amino acid proline in the GNAT family N-acetyltransferase enzyme, located in the symbiotic island A. GNATs comprise a large superfamily of enzymes responsible for a variety of biological processes, catalysing the transfer of an acetyl group from acetyl coenzyme A (AcCoA) to substrates such as aminoglycoside antibiotics, amino acids, polyamines, peptides, vitamins, catecholamines and large macromolecules, including proteins. Consequently, GNATs play roles in a large number of biological processes, including aminoglycoside antibiotic resistance, transcriptional regulation, protein acetylation and stress response, allowing organisms to respond and adapt quickly to changing environmental conditions [70–72]. We found no studies with GNATs in B.…”

An acetyltransferase controls the metabolic flux in rubromycin polyketide biosynthesis by direct modulation of redox tailoring enzymes

“…GNATs typically have a strictly conserved fold, ideally suited for homology modeling. 27,33,34 Accordingly, the predicted structure of HyalJ revealed the putative AcCoA binding site as well as catalytic residues. Based on its position, His81 may thus function as critical residue of the oxyanion hole for stabilization of the negative charge in the transition state following the attack of GrhO6's K5 side chain on the thioester bond of the CoA-ester substrates.…”

A Carotenoid- and Nuclease-Producing Bacterium Can Mitigate Enterococcus faecalis Transformation by Antibiotic Resistance Genes

“…Thioredoxin systems are employed by bacteria to defend against oxidative stress and maintain protein function, while redox homeostasis is indispensable for maintaining cellular processes (e.g., ROS response, redox reaction, signaling, xenobiotic removal, and protection of protein thiols) . In addition, genes coding for PFAM response regulator (external environment stimulus responses) and aminoglycoside and bleomycin resistance (bleomycin resistance dioxygenase and GNAT family enzymes) were also higher in the Ef-Dr set. These findings indicate that D. radiodurans first strengthened its own protection to survive exposure to antibiotics, making it possible to further protect neighboring E. faecalis .…”