title: Identification of photoactivated adenylyl cyclases in Naegleria australiensis and BLUF-containing protein in Naegleria fowleri.
abstract: Complete genome sequencing of Naegleria gruberi has revealed that the organism encodes polypeptides similar to photoactivated adenylyl cyclases (PACs). Screening in the N. australiensis genome showed that the organism also encodes polypeptides similar to PACs. Each of the Naegleria proteins consists of a "sensors of blue-light using FAD" domain (BLUF domain) and an adenylyl cyclase domain (AC domain). PAC activity of the Naegleria proteins was assayed by comparing sensitivities of Escherichia coli cells heterologously expressing the proteins to antibiotics in a dark condition and a blue light-irradiated condition. Antibiotics used in the assays were fosfomycin and fosmidomycin. E. coli cells expressing the Naegleria proteins showed increased fosfomycin sensitivity and fosmidomycin sensitivity when incubated under blue light, indicating that the proteins functioned as PACs in the bacterial cells. Analysis of the N. fowleri genome revealed that the organism encodes a protein bearing an amino acid sequence similar to that of BLUF. A plasmid expressing a chimeric protein consisting of the BLUF-like sequence found in N. fowleri and the adenylyl cyclase domain of N. gruberi PAC was constructed to determine whether the BLUF-like sequence functioned as a sensor of blue light. E. coli cells expressing a chimeric protein showed increased fosfomycin sensitivity and fosmidomycin sensitivity when incubated under blue light. These experimental results indicated that the sequence similar to the BLUF domain found in N. fowleri functioned as a sensor of blue light.
authors.affiliation: Academic Group of Applied Life Sciences, Iwate University.
authors.forename: Hiro
authors.initials: H
authors.lastname: Yasukawa
authors.forename: Aya
authors.initials: A
authors.lastname: Sato
authors.forename: Ayaka
authors.initials: A
authors.lastname: Kita
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Kodaira
authors.forename: Mineo
authors.initials: M
authors.lastname: Iseki
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Takahashi
authors.forename: Mami
authors.initials: M
authors.lastname: Shibusawa
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Watanabe
authors.forename: Kenji
authors.initials: K
authors.lastname: Yagita
mesh_terms: D000262:Adenylyl Cyclases / Q000235:genetics* / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D003624:Darkness; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D005578:Fosfomycin / Q000031:analogs & derivatives / Q000494:pharmacology; D015870:Gene Expression; D008027:Light; D008826:Microbial Sensitivity Tests; D009253:Naegleria / Q000201:enzymology* / Q000235:genetics; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D011994:Recombinant Proteins; D005578:Fosfomycin; C024640:fosmidomycin; D000262:Adenylyl Cyclases