PMID:20971910

Citation	Heffron, JD, Sherry, N and Popham, DL (2011) In vitro studies of peptidoglycan binding and hydrolysis by the Bacillus anthracis germination-specific lytic enzyme SleB. J. Bacteriol. 193:125-31
Abstract	The Bacillus anthracis endospore loses resistance properties during germination when its cortex peptidoglycan is degraded by germination-specific lytic enzymes (GSLEs). Although this event normally employs several GSLEs for complete cortex removal, the SleB protein alone can facilitate enough cortex hydrolysis to produce vulnerable spores. As a means to better understand its enzymatic function, SleB was overexpressed, purified, and tested in vitro for depolymerization of cortex by measurement of optical density loss and the solubilization of substrate. Its ability to bind peptidoglycan was also investigated. SleB functions independently as a lytic transglycosylase on both intact and fragmented cortex. Most of the muropeptide products that SleB generates are large and are potential substrates for other GSLEs present in the spore. Study of a truncated protein revealed that SleB has two domains. The N-terminal domain is required for stable peptidoglycan binding, while the C-terminal domain is the region of peptidoglycan hydrolytic activity. The C-terminal domain also exhibits dependence on cortex containing muramic-δ-lactam in order to carry out hydrolysis. As the conditions and limitations for SleB activity are further elucidated, they will enable the development of treatments that stimulate premature germination of B. anthracis spores, greatly simplifying decontamination measures.
Links	PubMed PMC3019929 Online version:10.1128/JB.00869-10
Keywords	Amidohydrolases/genetics; Amidohydrolases/metabolism; Bacillus anthracis/enzymology; Bacillus anthracis/genetics; Bacillus anthracis/metabolism; Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Gene Expression Regulation, Bacterial/physiology; Hydrolysis; Lactams/metabolism; Muramic Acids/metabolism; Peptidoglycan/genetics; Peptidoglycan/metabolism; Protein Binding; Protein Conformation
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
BACAN:Q81PQ3		GO:0003796: lysozyme activity	ECO:0000315:		F		SleB functions to breaks down peptidoglycan (PG) by hydrolysis this is known as lysozyme activity. Table 1 compares the WT and mutant forms of the protein SleB. The WT form of the protein leads to 96% of the PG being solubilized whereas the mutant form only leads to 14% of the PG being solubilized.	complete CACAO 4310
BACAN:Q81PQ3	enables	GO:0003796: lysozyme activity	ECO:0000315: mutant phenotype evidence used in manual assertion		F		Seeded From UniProt	complete

References

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