Dataset Information

The Anti-sigma Factor RsiV Is a Bacterial Receptor for Lysozyme: Co-crystal Structure Determination and Demonstration That Binding of Lysozyme to RsiV Is Required for ?V Activation.

ABSTRACT: ? factors provide RNA polymerase with promoter specificity in bacteria. Some ? factors require activation in order to interact with RNA polymerase and transcribe target genes. The Extra-Cytoplasmic Function (ECF) ? factor, ?V, is encoded by several Gram-positive bacteria and is specifically activated by lysozyme. This activation requires the proteolytic destruction of the anti-? factor RsiV via a process of regulated intramembrane proteolysis (RIP). In many cases proteases that cleave at site-1 are thought to directly sense a signal and initiate the RIP process. We previously suggested binding of lysozyme to RsiV initiated the proteolytic destruction of RsiV and activation of ?V. Here we determined the X-ray crystal structure of the RsiV-lysozyme complex at 2.3 Å which revealed that RsiV and lysozyme make extensive contacts. We constructed RsiV mutants with altered abilities to bind lysozyme. We find that mutants that are unable to bind lysozyme block site-1 cleavage of RsiV and ?V activation in response to lysozyme. Taken together these data demonstrate that RsiV is a receptor for lysozyme and binding of RsiV to lysozyme is required for ?V activation. In addition, the co-structure revealed that RsiV binds to the lysozyme active site pocket. We provide evidence that in addition to acting as a sensor for the presence of lysozyme, RsiV also inhibits lysozyme activity. Thus we have demonstrated that RsiV is a protein with multiple functions. RsiV inhibits ?V activity in the absence of lysozyme, RsiV binds lysozyme triggering ?V activation and RsiV inhibits the enzymatic activity of lysozyme.

SUBMITTER: Hastie JL

PROVIDER: S-EPMC5014341 | biostudies-literature | 2016 Sep

REPOSITORIES: biostudies-literature

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Publications

The Anti-sigma Factor RsiV Is a Bacterial Receptor for Lysozyme: Co-crystal Structure Determination and Demonstration That Binding of Lysozyme to RsiV Is Required for σV Activation.

Hastie Jessica L JL Williams Kyle B KB Bohr Lindsey L LL Houtman Jon C JC Gakhar Lokesh L Ellermeier Craig D CD

PLoS genetics 20160907 9

σ factors provide RNA polymerase with promoter specificity in bacteria. Some σ factors require activation in order to interact with RNA polymerase and transcribe target genes. The Extra-Cytoplasmic Function (ECF) σ factor, σV, is encoded by several Gram-positive bacteria and is specifically activated by lysozyme. This activation requires the proteolytic destruction of the anti-σ factor RsiV via a process of regulated intramembrane proteolysis (RIP). In many cases proteases that cleave at site-1 ...[more]

PMID: 27602573

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Project description:Extracytoplasmic function (ECF) ? factors are a diverse family of alternative ? factors that allow bacteria to sense and respond to changes in the environment. ?V is an ECF ? factor found primarily in low-GC Gram-positive bacteria and is required for lysozyme resistance in several opportunistic pathogens. In the absence of lysozyme, ?V is inhibited by the anti-? factor RsiV. In response to lysozyme, RsiV is degraded via the process of regulated intramembrane proteolysis (RIP). RIP is initiated by cleavage of RsiV at site 1, which allows the intramembrane protease RasP to cleave RsiV within the transmembrane domain at site 2 and leads to activation of ?V Previous work suggested that RsiV is cleaved by signal peptidase at site 1. Here we demonstrate in vitro that signal peptidase is sufficient for cleavage of RsiV only in the presence of lysozyme and provide evidence that multiple Bacillus subtilis signal peptidases can cleave RsiV in vitro This cleavage is dependent upon the concentration of lysozyme, consistent with previous work that showed that binding to RsiV was required for ?V activation. We also show that signal peptidase activity is required for site 1 cleavage of RsiV in vivo Thus, we demonstrate that signal peptidase is the site 1 protease for RsiV.IMPORTANCE Extracytoplasmic function (ECF) ? factors are a diverse family of alternative ? factors that respond to extracellular signals. The ECF ? factor ?V is present in many low-GC Gram-positive bacteria and induces resistance to lysozyme, a component of the innate immune system. The anti-? factor RsiV inhibits ?V activity in the absence of lysozyme. Lysozyme binds RsiV, which initiates a proteolytic cascade leading to destruction of RsiV and activation of ?V This proteolytic cascade is initiated by signal peptidase, a component of the general secretory system. We show that signal peptidase is necessary and sufficient for cleavage of RsiV at site 1 in the presence of lysozyme. This report describes a role for signal peptidase in controlling gene expression.

Dataset Information

The Anti-sigma Factor RsiV Is a Bacterial Receptor for Lysozyme: Co-crystal Structure Determination and Demonstration That Binding of Lysozyme to RsiV Is Required for ?V Activation.

Publications

The Anti-sigma Factor RsiV Is a Bacterial Receptor for Lysozyme: Co-crystal Structure Determination and Demonstration That Binding of Lysozyme to RsiV Is Required for σV Activation.

Similar Datasets

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