title: The E. coli sirtuin CobB shows no preference for enzymatic and nonenzymatic lysine acetylation substrate sites.
abstract: N(ε) -lysine acetylation is an abundant posttranslational modification of thousands of proteins involved in diverse cellular processes. In the model bacterium Escherichia coli, the ε-amino group of a lysine residue can be acetylated either catalytically by acetyl-coenzyme A (acCoA) and lysine acetyltransferases, or nonenzymatically by acetyl phosphate (acP). It is well known that catalytic acCoA-dependent N(ε) -lysine acetylation can be reversed by deacetylases. Here, we provide genetic, mass spectrometric, structural and immunological evidence that CobB, a deacetylase of the sirtuin family of NAD(+) -dependent deacetylases, can reverse acetylation regardless of acetyl donor or acetylation mechanism. We analyzed 69 lysines on 51 proteins that we had previously detected as robustly, reproducibly, and significantly more acetylated in a cobB mutant than in its wild-type parent. Functional and pathway enrichment analyses supported the hypothesis that CobB regulates protein function in diverse and often essential cellular processes, most notably translation. Combined mass spectrometry, bioinformatics, and protein structural data provided evidence that the accessibility and three-dimensional microenvironment of the target acetyllysine help determine CobB specificity. Finally, we provide evidence that CobB is the predominate deacetylase in E. coli.
authors.affiliation: Department of Microbiology and Immunology, Loyola University Chicago, Health Sciences Division, Stritch School of Medicine, Maywood, Illinois, 60153; Department of Microbiology, Faculty of Pharmacy, Alexandria University, Alexandria, 21521, Egypt.
authors.forename: Alaa
authors.initials: A
authors.lastname: AbouElfetouh
authors.forename: Misty L
authors.initials: ML
authors.lastname: Kuhn
authors.forename: Linda I
authors.initials: LI
authors.lastname: Hu
authors.forename: Michael D
authors.initials: MD
authors.lastname: Scholle
authors.forename: Dylan J
authors.initials: DJ
authors.lastname: Sorensen
authors.forename: Alexandria K
authors.initials: AK
authors.lastname: Sahu
authors.forename: Dörte
authors.initials: D
authors.lastname: Becher
authors.forename: Haike
authors.initials: H
authors.lastname: Antelmann
authors.forename: Milan
authors.initials: M
authors.lastname: Mrksich
authors.forename: Wayne F
authors.initials: WF
authors.lastname: Anderson
authors.forename: Bradford W
authors.initials: BW
authors.lastname: Gibson
authors.forename: Birgit
authors.initials: B
authors.lastname: Schilling
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Wolfe
mesh_terms: D000107:Acetylation; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism*; D037761:Sirtuins / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D029968:Escherichia coli Proteins; D037761:Sirtuins; C483998:cobB protein, E Coli; D008239:Lysine
keywords: Acetyl phosphate; bacteria; crystallography; deacetylase; mass spectrometry; posttranslational modification