title: Molecular mechanism underlying promiscuous polyamine recognition by spermidine acetyltransferase.
abstract: Spermidine acetyltransferase (SAT) from Escherichia coli, which catalyses the transfer of acetyl groups from acetyl-CoA to spermidine, is a key enzyme in controlling polyamine levels in prokaryotic cells. In this study, we determined the crystal structure of SAT in complex with spermidine (SPD) and CoA at 2.5Å resolution. SAT is a dodecamer organized as a hexamer of dimers. The secondary structural element and folding topology of the SAT dimer resemble those of spermidine/spermine N(1)-acetyltransferase (SSAT), suggesting an evolutionary link between SAT and SSAT. However, the polyamine specificity of SAT is distinct from that of SSAT and is promiscuous. The SPD molecule is also located at the inter-dimer interface. The distance between SPD and CoA molecules is 13Å. A deep, highly acidic, water-filled cavity encompasses the SPD and CoA binding sites. Structure-based mutagenesis and in-vitro assays identified SPD-bound residues, and the acidic residues lining the walls of the cavity are mostly essential for enzymatic activities. Based on mutagenesis and structural data, we propose an acetylation mechanism underlying promiscuous polyamine recognition for SAT.
authors.affiliation: Graduate School of Science, Osaka University, Suita, Osaka 565-0871, Japan; JST, ERATO, Lipid Active Structure Project, Osaka 565-0871, Japan. Electronic address: sugiyama@cryst.eei.eng.osaka-u.ac.jp.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Sugiyama
authors.affiliation: Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan.
authors.forename: Sae
authors.initials: S
authors.lastname: Ishikawa
authors.affiliation: Faculty of Pharmacy, Chiba Institute of Science, Choshi, Chiba 288-0025, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Tomitori
authors.affiliation: Graduate School of Science, Osaka University, Suita, Osaka 565-0871, Japan; JST, ERATO, Lipid Active Structure Project, Osaka 565-0871, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Niiyama
authors.affiliation: Graduate School of Science, Osaka University, Suita, Osaka 565-0871, Japan; JST, ERATO, Lipid Active Structure Project, Osaka 565-0871, Japan.
authors.forename: Mika
authors.initials: M
authors.lastname: Hirose
authors.affiliation: Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan.
authors.forename: Yuma
authors.initials: Y
authors.lastname: Miyazaki
authors.affiliation: Graduate School of Pharmaceutical Sciences, Chiba University, Chuo-ku, Chiba 260-8675, Japan.
authors.forename: Kyohei
authors.initials: K
authors.lastname: Higashi
authors.affiliation: Graduate School of Science, Osaka University, Suita, Osaka 565-0871, Japan; JST, ERATO, Lipid Active Structure Project, Osaka 565-0871, Japan.
authors.forename: Michio
authors.initials: M
authors.lastname: Murata
authors.affiliation: Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan; SOSHO Inc., Suita, Osaka 565-0871, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Adachi
authors.affiliation: SOSHO Inc., Suita, Osaka 565-0871, Japan; Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto 606-8522, Japan.
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Takano
authors.affiliation: SOSHO Inc., Suita, Osaka 565-0871, Japan; Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8501, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Murakami
authors.affiliation: Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan; SOSHO Inc., Suita, Osaka 565-0871, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Inoue
authors.affiliation: Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan; SOSHO Inc., Suita, Osaka 565-0871, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Mori
authors.affiliation: Faculty of Pharmacy, Chiba Institute of Science, Choshi, Chiba 288-0025, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Kashiwagi
authors.affiliation: Graduate School of Pharmaceutical Sciences, Chiba University, Chuo-ku, Chiba 260-8675, Japan; Amine Pharma Research Institute, Innovation Plaza at Chiba University, Chuo-ku, Chiba 260-0856, Japan.
authors.forename: Kazuei
authors.initials: K
authors.lastname: Igarashi
authors.affiliation: SOSHO Inc., Suita, Osaka 565-0871, Japan; Department of Biotechnology, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan. Electronic address: h-matsu@fc.ritsumei.ac.jp.
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Matsumura
mesh_terms: D000107:Acetylation; D000123:Acetyltransferases / Q000737:chemistry*; D001665:Binding Sites; D015317:Biogenic Polyamines / Q000737:chemistry*; D003065:Coenzyme A / Q000737:chemistry; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000737:chemistry*; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D013379:Substrate Specificity; D000099228:Diamine N-Acetyltransferase
chemical_list: D000123:Acetyltransferases; D015317:Biogenic Polyamines; D003065:Coenzyme A; D029968:Escherichia coli Proteins; D000099228:Diamine N-Acetyltransferase
keywords: Acetyl-CoA; Dodecamer; SAT; SPD