title: An active site tyrosine residue is essential for amidohydrolase but not for esterase activity of a class 2 histone deacetylase-like bacterial enzyme.
abstract: HDACs (histone deacetylases) are considered to be among the most important enzymes that regulate gene expression in eukaryotic cells acting through deacetylation of epsilon-acetyl-lysine residues within the N-terminal tail of core histones. In addition, both eukaryotic HDACs as well as their bacterial counterparts were reported to also act on non-histone targets. However, we are still far from a comprehensive understanding of the biological activities of this ancient class of enzymes. In the present paper, we studied in more detail the esterase activity of HDACs, focussing on the HDAH (histone deacetylase-like amidohydrolase) from Bordetella/Alcaligenes strain FB188. This enzyme was classified as a class 2 HDAC based on sequence comparison as well as functional data. Using chromogenic and fluorogenic ester substrates we show that HDACs such as FB188 HDAH indeed have esterase activity that is comparable with those of known esterases. Similar results were obtained for human HDAC1, 3 and 8. Standard HDAC inhibitors were able to block both activities with similar IC(50) values. Interestingly, HDAC inhibitors such as suberoylanilide hydroxamic acid (SAHA) also showed inhibitory activity against porcine liver esterase and Pseudomonas fluorescens lipase. The esterase and the amidohydrolase activity of FB188 HDAH both appear to have the same substrate specificity concerning the acyl moiety. Interestingly, a Y312F mutation in the active site of HDAH obstructed amidohydrolase activity but significantly improved esterase activity, indicating subtle differences in the mechanism of both catalytic activities. Our results suggest that, in principle, HDACs may have other biological roles besides acting as protein deacetylases. Furthermore, data on HDAC inhibitors affecting known esterases indicate that these molecules, which are currently among the most promising drug candidates in cancer therapy, may have a broader target profile requiring further exploration.
authors.affiliation: Department of Molecular Genetics and Preparative Molecular Biology, Institute for Microbiology and Genetics, Grisebachstr. 8, 37077 Goettingen, Germany.
authors.forename: Kristin
authors.initials: K
authors.lastname: Moreth
authors.forename: Daniel
authors.initials: D
authors.lastname: Riester
authors.forename: Christian
authors.initials: C
authors.lastname: Hildmann
authors.forename: René
authors.initials: R
authors.lastname: Hempel
authors.forename: Dennis
authors.initials: D
authors.lastname: Wegener
authors.forename: Andreas
authors.initials: A
authors.lastname: Schober
authors.forename: Andreas
authors.initials: A
authors.lastname: Schwienhorst
mesh_terms: D000421:Alcaligenes / Q000201:enzymology*; D000581:Amidohydrolases / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D001884:Bordetella / Q000201:enzymology*; D004950:Esterases / Q000737:chemistry / Q000378:metabolism*; D006655:Histone Deacetylases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015394:Molecular Structure; D009154:Mutation; D013379:Substrate Specificity; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D014443:Tyrosine; D004950:Esterases; D000581:Amidohydrolases; D006655:Histone Deacetylases