title: Acinetobacter baylyi long-term stationary-phase protein StiP is a protease required for normal cell morphology and resistance to tellurite.
abstract: We investigated the Acinetobacter baylyi gene ACIAD1960, known from previous work to be expressed during long-term stationary phase. The protein encoded by this gene had been annotated as a Conserved Hypothetical Protein, surrounded by putative tellurite resistance ("Ter") proteins. Sequence analysis suggested that the protein belongs to the DUF1796 putative papain-like protease family. Here, we show that the purified protein, subsequently named StiP, has cysteine protease activity. Deletion of stiP causes hypersensitivity to tellurite, altered population dynamics during long-term batch culture, and most strikingly, dramatic alteration of normal cell morphology. StiP and associated Ter proteins (the StiP-Ter cluster) are therefore important for regulating cell morphology, likely in response to oxidative damage or depletion of intracellular thiol pools, triggered artificially by tellurite exposure. Our finding has broad significance because while tellurite is an extremely rare compound in nature, oxidative damage, the need to maintain a particular balance of intracellular thiols, and the need to regulate cell morphology are ubiquitous.
authors.affiliation: a Department of Chemistry and Biochemistry, Colorado College, 14 East Cache La Poudre Avenue, Colorado Springs, CO 80903, USA.
authors.forename: Blake
authors.initials: B
authors.lastname: Reichert
authors.forename: Amber J
authors.initials: AJ
authors.lastname: Dornbusch
authors.forename: Joshua
authors.initials: J
authors.lastname: Arguello
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Stanley
authors.forename: Kristine M
authors.initials: KM
authors.lastname: Lang
authors.forename: C Phoebe
authors.initials: CP
authors.lastname: Lostroh
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Daugherty
mesh_terms: D000150:Acinetobacter / Q000737:chemistry* / Q000166:cytology / Q000187:drug effects / Q000235:genetics; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D003001:Cloning, Molecular; D019295:Computational Biology; D057056:Cysteine Proteases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D005798:Genes, Bacterial; D054643:INDEL Mutation; D005810:Multigene Family; D010084:Oxidation-Reduction; D017434:Protein Structure, Tertiary; D012988:Soil Microbiology; D013691:Tellurium / Q000494:pharmacology*
chemical_list: D001426:Bacterial Proteins; D057056:Cysteine Proteases; C026660:tellurous acid; D013691:Tellurium