Project description:Emerging discoveries about undocumented acyltransferase activities of known histone acetyltransferases (HATs) advance our understandings in the regulation of histone modifications. However, the molecular basis of HATs selecting acyl coenzyme A (acyl-CoA) substrates for histone modification is less known. We here report that lysine acetyltransferase 2A (KAT2A) as an illustrative instance of HATs can selectively utilize acetyl-CoA, propionyl-CoA, butyryl-CoA, and succinyl-CoA to directly deposit 18 histone acylation hallmarks in nucleosome. By analyzing the co-crystal structures of the catalytic domain of KAT2A in complex with acetyl-CoA, propionyl-CoA, butyryl-CoA, malonyl-CoA, succinyl-CoA, and glutaryl-CoA, we conclude that the alternative substrate-binding pocket of KAT2A and the length and electrostatic features of the acyl chain cooperatively determine the selection of the acyl-CoA substrates by KAT2A. This study reveals the molecular basis underlying the pluripotency of HATs that selectively install acylation hallmarks in nucleosomes, which might serve as instrumental mechanism to precisely regulate histone acylation profiles in cells.
Project description:Succinyl-CoA synthetase (SCS) catalyzes the only substrate-level phosphorylation step in the tricarboxylic acid cycle. Human GTP-specific SCS (GTPSCS), an αβ-heterodimer, was produced in Escherichia coli. The purified protein crystallized from a solution containing tartrate, CoA and magnesium chloride, and a crystal diffracted to 1.52 Å resolution. Tartryl-CoA was discovered to be bound to GTPSCS. The CoA portion lies in the amino-terminal domain of the α-subunit and the tartryl end extends towards the catalytic histidine residue. The terminal carboxylate binds to the phosphate-binding site of GTPSCS.
Project description:Lysine-succinylation is a subtype of protein acylation associated with metabolic regulation of succinyl-CoA in the TCA cycle. Deficiency of succinyl-CoA synthetase (SCS), the TCA-cycle enzyme catalyzing the reversible conversion of succinyl-CoA to succinate, leads to mitochondrial encephalomyopathy in humans and embryonic lethality in mice. This report presents a conditional forebrain-specific knock-out (KO0 mouse model of Sucla2, the gene encoding the ATP-specific beta isoform of SCS, resulting in postnatal deficiency of the entire SCS complex. Results demonstrate that the accumulation of succinyl-CoA in the absence of SCS leads to hyper-succinylation within the cerebral cortex of adult mice. With previous research identifying succinylation marks on histones, and with proteomic evidence of histone lysine-succinylation within the presented model, global chromatin accessibility was surveyed in Sucla2 mutant and control mice via ATAC-sequencing. Data show wide-scale alterations in chromatin landscape and global gene expression. Computational analysis of combined chromatin-accessibility and gene expression data reveal perturbation of neuronal transcriptional regulatory networks in the mutant forebrain, suggesting SCS-related changes in the protein succinylome and chromatin accessibility play a significant role in the neuronal pathogenesis of SCS-deficiency.
Project description:Lysine-succinylation is a subtype of protein acylation associated with metabolic regulation of succinyl-CoA in the TCA cycle. Deficiency of succinyl-CoA synthetase (SCS), the TCA-cycle enzyme catalyzing the reversible conversion of succinyl-CoA to succinate, leads to mitochondrial encephalomyopathy in humans and embryonic lethality in mice. This report presents a conditional forebrain-specific knock-out (KO0 mouse model of Sucla2, the gene encoding the ATP-specific beta isoform of SCS, resulting in postnatal deficiency of the entire SCS complex. Results demonstrate that the accumulation of succinyl-CoA in the absence of SCS leads to hyper-succinylation within the cerebral cortex of adult mice. With previous research identifying succinylation marks on histones, and with proteomic evidence of histone lysine-succinylation within the presented model, global chromatin accessibility was surveyed in Sucla2 mutant and control mice via ATAC-sequencing. Data show wide-scale alterations in chromatin landscape and global gene expression. Computational analysis of combined chromatin-accessibility and gene expression data reveal perturbation of neuronal transcriptional regulatory networks in the mutant forebrain, suggesting SCS-related changes in the protein succinylome and chromatin accessibility play a significant role in the neuronal pathogenesis of SCS-deficiency.
Project description:This patient presented on the first day of life with pronounced lactic acidosis with an elevated lactate/pyruvate ratio. Urine organic acids showed Krebs cycle metabolites and mildly elevated methylmalonate and methylcitrate. The acylcarnitine profile showed elevated propionylcarnitine and succinylcarnitine. Amino acids showed elevated glutamic acid, glutamine, proline, and alanine. From the age 2 of mo on, she had elevated transaminases and intermittent episodes of liver failure. Liver biopsy showed steatosis and a decrease of mitochondrial DNA to 50% of control. She had bilateral sensorineural hearing loss. Over the course of the first 2 y of life, she developed a progressively severe myopathy with pronounced muscle weakness eventually leading to respiratory failure, Leigh disease, and recurrent hepatic failure. The hepatic symptoms and the metabolic parameters temporarily improved on treatment with aspartate, but neither muscle symptoms nor brain lesions improved. Laboratory testing revealed a deficiency of succinyl-CoA ligase enzyme activity and protein in fibroblasts because of a novel homozygous mutation in the SUCLG1 gene: c.40A>T (p.M14L). Functional analysis suggests that this methionine is more likely to function as the translation initiator methionine, explaining the pathogenic nature of the mutation. Succinyl-CoA ligase deficiency due to an SUCLG1 mutation is a new cause for mitochondrial hepatoencephalomyopathy.
Project description:Pig GTP-specific succinyl-CoA synthetase is an αβ-heterodimer. The crystal structure of the complex with the substrate CoA was determined at 2.1 Å resolution. The structure shows CoA bound to the amino-terminal domain of the α-subunit, with the free thiol extending from the adenine portion into the site where the catalytic histidine residue resides.
Project description:Succinyl-CoA:3-ketoacid CoA transferase (SCOT) plays a crucial role in ketone-body metabolism. SCOT from Drosophila melanogaster (DmSCOT) was purified and crystallized. The crystal structure of DmSCOT was determined at 2.64 Å resolution and belonged to space group P212121, with unit-cell parameters a=76.638, b=101.921, c=122.457 Å, α=β=γ=90°. Sequence alignment and structural analysis identified DmSCOT as a class I CoA transferase. Compared with Acetobacter aceti succinyl-CoA:acetate CoA transferase, DmSCOT has a different substrate-binding pocket, which may explain the difference in their substrate specificities.
Project description:Protein post-translational modifications serve to regulate a broad range of cellular functions including signal transduction, transcription, and metabolism. Protein lysine residues undergo many post-translational acylations and are regulated by a range of enzymes, such as histone acetyl transferases (HATs) and histone deacetylases (HDACs). KAT2A, well characterized as a lysine acetyltransferase for both histone and nonhistone substrates, has been reported to tolerate additional acyl-CoA substrates, such as succinyl-CoA, and shows nonacetyl transferase activity in specific biological contexts. In this work, we investigate the acyl-CoA substrate preference of KAT2A and attempt to determine whether and to what extent additional acyl-CoA substrates may be utilized by KAT2A in a cellular context. We show that while KAT2A can bind and utilize malonyl-CoA, its activity with succinyl-CoA or glutaryl-CoA is very weak, and acetylation is still the most efficient activity for KAT2A in vitro and in cells.