Study Identifies Protease Enzyme Controlling Flagellin Turnover and Development in Predatory Bacterium
Researchers have characterized Bd0967, a previously unstudied carboxy-terminal processing protease (CTP) in the predatory bacterium Bdellovibrio bacteriovorus, finding it plays a key role in breaking down flagellin proteins during the organism's predatory life cycle. Crystal structures revealed a self-compartmentalized architecture, and mass spectrometry identified multiple flagellins as substrates degraded via a conserved C-terminal recognition motif. Deletion of the gene caused abnormal cell morphology and reduced predation efficiency, suggesting Bd0967 couples flagellar resorption to developmental progression.
A new study published on bioRxiv characterizes Bd0967, a carboxy-terminal processing protease (CTP) from Bdellovibrio bacteriovorus, a bacterium that preys on other gram-negative bacteria. Crystal structures of Bd0967 revealed a self-compartmentalized protease featuring a PDZ domain that acts as a lid over a large internal cavity accessible through a proteolytic tunnel, with co-purifying peptides occupying two distinct substrate-binding sites indicative of a coordinated recognition mechanism. Affinity pulldown experiments coupled with mass spectrometry identified several Bdellovibrio flagellins as candidate substrates, which were biochemically validated and shown to be selectively degraded through recognition of a conserved C-terminal motif. A fluorescent fusion of Bd0967 localized to periplasmic foci during intracellular predatory growth, consistent with a role in flagellar resorption after prey invasion. Deletion of bd0967 produced developmental defects including aberrant cell morphology and diminished predation efficiency, establishing a functional link between flagellin turnover and developmental progression. CTPs are broadly conserved across bacteria and implicated in protein maturation and stress responses, but the specific functions of many family members have remained poorly understood; this work provides a detailed mechanistic account of one such member.
What's missing
As a preprint, this study has not yet undergone formal peer review, so findings should be interpreted with caution. The study does not address whether Bd0967 homologs in other bacterial species perform analogous roles in flagellar resorption, nor does it explore whether the identified C-terminal recognition motif is sufficient on its own to direct substrate targeting in vivo.
What different sources said
- bioRxivCenter
A C-terminal Processing Protease Implicated in Flagellin Turnover and Developmental Progression in a Bacterial Predator
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