title: Deletion of degQ gene enhances outer membrane vesicle production of Shewanella oneidensis cells.
abstract: Shewanella oneidensis is a Gram-negative facultative anaerobe that can use a wide variety of terminal electron acceptors for anaerobic respiration. In this study, S. oneidensis degQ gene, encoding a putative periplasmic serine protease, was cloned and expressed. The activity of purified DegQ was inhibited by diisopropyl fluorophosphate, a typical serine protease-specific inhibitor, indicating that DegQ is a serine protease. In-frame deletion and subsequent complementation of the degQ were carried out to examine the effect of envelope stress on the production of outer membrane vesicles (OMVs). Analysis of periplasmic proteins from the resulting S. oneidensis strain showed that deletion of degQ induced protein accumulation and resulted in a significant decrease in protease activity within the periplasmic space. OMVs from the wild-type and mutant strains were purified and observed by transmission electron microscopy. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the OMVs showed a prominent band at ~37 kDa. Nanoliquid chromatography-tandem mass spectrometry analysis identified three outer membrane porins (SO3896, SO1821, and SO3545) as dominant components of the band, suggesting that these proteins could be used as indices for comparing OMV production by S. oneidensis strains. Quantitative evaluation showed that degQ-deficient cells had a fivefold increase in OMV production compared with wild-type cells. Thus, the increased OMV production following the deletion of DegQ in S. oneidensis may be responsible for the increase in envelope stress.
authors: Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka, 560-8531, Japan. ojima@bioa.eng.osaka-cu.ac.jp.|Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan. ojima@bioa.eng.osaka-cu.ac.jp.
authors: Yoshihiro
authors: Y
authors: Ojima
authors: Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka, 560-8531, Japan.
authors: Thivagaran
authors: T
authors: Mohanadas
authors: Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka, 560-8531, Japan.
authors: Kosei
authors: K
authors: Kitamura
authors: Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka, 560-8531, Japan.
authors: Shota
authors: S
authors: Nunogami
authors: Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka, 560-8531, Japan.
authors: Reiki
authors: R
authors: Yajima
authors: Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka, 560-8531, Japan.
authors: Masahito
authors: M
authors: Taya
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D004789:Enzyme Activation / Q000235:genetics; D017353:Gene Deletion; D005816:Genetic Complementation Test; D046529:Microscopy, Electron, Transmission; D010447:Peptide Hydrolases / Q000235:genetics* / Q000378:metabolism; D019897:Periplasm / Q000201:enzymology / Q000378:metabolism; D018272:Porins / Q000032:analysis / Q000235:genetics; D020592:Shewanella / Q000235:genetics* / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D001425:Bacterial Outer Membrane Proteins; D018272:Porins; D010447:Peptide Hydrolases
keywords: Outer membrane vesicle; Periplasmic serine protease; Shewanella oneidensis; degQ