Inactivation of extracellular proteases in Bacillus halodurans and the impact 2 on its modified flagellin type III secretion pathway 3 4

9 The flagellin type III secretion pathway of Bacillus halodurans BhFC01 (∆hag) was modified by 10 inactivation of fliD. An in frame flagellin fusion polypeptide construct was expressed and the 11 heterologous peptides secreted as flagellin fusion monomers. The stability of the secreted 12 monomers was significantly enhanced through gene-targeted inactivation of extracellular 13 proteases. 14 Corresponding author. Mailing address: CSIR Biosciences, Box 395, Pretoria 0001, South 15 Africa. Phone: 27 12 841-2167. Fax 27 12 841-3651. E-mail: [email protected] 16 17 Gram-negative bacteria use specialized systems to secrete selected proteins outside the cell. One 18 example is the type III secretion system whose substrates include virulence proteins (8). The 19 flagellar type III secretion apparatus efficiently secretes the flagellin subunit protein, FliC in both 20 Gram-negative and Gram-positive bacteria. Most flagellar components are translocated across the 21 cytoplasmic membrane by the flagellar type III system, and they self assemble at the distal end of 22 its narrow channel with the help of a cap structure. Flagellin filaments polymerize exterior to the 23 CC EP TE D Copyright © 2008, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved. Appl. Environ. Microbiol. doi:10.1128/AEM.02430-08 AEM Accepts, published online ahead of print on 7 November 2008 on O cber 2, 2017 by gest ht://aem .sm .rg/ D ow nladed fom