6pi8
Crystal structure of Marinobacter subterrani acetylpolyamine amidohydrolase (msAPAH) complexed with acetate
Structural highlights
FunctionPublication Abstract from PubMedPolyamines are small organic cations that are essential for cellular function in all kingdoms of life. Polyamine metabolism is regulated by enzyme-catalyzed acetylation-deacetylation cycles in a fashion similar to the epigenetic regulation of histone function in eukaryotes. Bacterial polyamine deacetylases are particularly intriguing, because these enzymes share the fold and function of eukaryotic histone deacetylases. Recently, acetylpolyamine amidohydrolase from the deep earth halophile Marinobacter subterrani (msAPAH) was described. This Zn(2+)-dependent deacetylase shares 53% amino acid sequence identity with the acetylpolyamine amidohydrolase from Mycoplana ramosa (mrAPAH) and 22% amino acid sequence identity with the catalytic domain of histone deacetylase 10 from Danio rerio (zebrafish; zHDAC10), the eukaryotic polyamine deacetylase. The X-ray crystal structure of msAPAH, determined in complexes with seven different inhibitors as well as the acetate coproduct, shows how the chemical strategy of Zn(2+)-dependent amide hydrolysis and the catalytic specificity for cationic polyamine substrates is conserved in a subterranean halophile. Structural comparisons with mrAPAH reveal that an array of aspartate and glutamate residues unique to msAPAH enable the binding of one or more Mg(2+) ions in the active site and elsewhere on the protein surface. Notwithstanding these differences, activity assays with a panel of acetylpolyamine and acetyllysine substrates confirm that msAPAH is a broad-specificity polyamine deacetylase, much like mrAPAH. The broad substrate specificity contrasts with the narrow substrate specificity of zHDAC10, which is highly specific for N(8)-acetylspermidine hydrolysis. Notably, quaternary structural features govern the substrate specificity of msAPAH and mrAPAH, whereas tertiary structural features govern the substrate specificity of zHDAC10. Structure and Function of the Acetylpolyamine Amidohydrolase from the Deep Earth Halophile Marinobacter subterrani.,Osko JD, Roose BW, Shinsky SA, Christianson DW Biochemistry. 2019 Sep 10;58(36):3755-3766. doi: 10.1021/acs.biochem.9b00582., Epub 2019 Aug 27. PMID:31436969[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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