title: Characterization of a novel thermostable N-acylhomoserine lactonase from the thermophilic bacterium Thermaerobacter marianensis.
abstract: Thermaerobacter marianensis is an extremely thermophilic bacterium, which was isolated from the Mariana Trench, with an optimal growth temperature of approximately 75 °C. N-Acylhomoserine lactone (AHL) is a quorum-sensing signal molecule used by many gram-negative bacteria. Here, we report the identification of an AHL-degrading gene homolog (designated aiiT) in the genome of T. marianensis JCM 10246. AiiT has 59.7%, 21.2%, and 11.2% identity to AhlS from Solibacillus silvestris, AiiA from Bacillus cereus, and AidC from Chryseobacterium sp., respectively. Homologs of aiiT were also found in Thermaerobacter nagasakiensis, T. composti, and T. subterraneus. A purified AiiT-maltose binding fusion showed high AHL-degrading activity against N-hexanoyl-L-homoserine lactone, N-octanoyl-L-homoserine lactone, and N-decanoyl-L-homoserine lactone at temperatures ranging from 40 to 80 °C. HPLC analysis revealed that AiiT functions as an AHL-lactonase that catalyzes AHL ring opening by hydrolyzing lactones. AiiT displayed maximal activity at high temperatures (60-80 °C) and showed higher thermostability than other AHL lactonases.
authors.affiliation: Department of Material and Environmental Chemistry, Graduate School of Engineering, Utsunomiya University, 7-1-2 Yoto, Utsunomiya 321-8585, Japan. Electronic address: morohosi@cc.utsunomiya-u.ac.jp.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Morohoshi
authors.affiliation: Department of Material and Environmental Chemistry, Graduate School of Engineering, Utsunomiya University, 7-1-2 Yoto, Utsunomiya 321-8585, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Tominaga
authors.affiliation: Hokkaido Agricultural Research Center (HARC), National Agriculture and Food Research Organization (NARO), 9-4 Shinsei-minami, Memuro-cho, Kasai-gun, Hokkaido 082-0081, Japan.
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Someya
authors.affiliation: Department of Material and Environmental Chemistry, Graduate School of Engineering, Utsunomiya University, 7-1-2 Yoto, Utsunomiya 321-8585, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Ikeda
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D001407:Bacillus / Q000201:enzymology / Q000235:genetics; D001409:Bacillus cereus; D001420:Bacteria, Aerobic / Q000201:enzymology* / Q000235:genetics; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism*; D004795:Enzyme Stability; D006714:Homoserine / Q000031:analogs & derivatives / Q000378:metabolism; D006868:Hydrolysis; D007783:Lactones / Q000378:metabolism; D058641:Planococcaceae / Q000201:enzymology / Q000235:genetics; D053038:Quorum Sensing; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D007783:Lactones; C104908:N-hexanoyl-L-homoserine lactone; C091088:N-octanoylhomoserine lactone; C088386:homoserine lactone; D006714:Homoserine; D002265:Carboxylic Ester Hydrolases; C020579:gluconolactonase; D015107:4-Butyrolactone
keywords: Acylhomoserine lactone; Lactonase; Quorum sensing; Thermaerobacter; Thermostable enzyme