Characterization of LytH, a Differentiation-Associated Peptidoglycan Hydrolase of Bacillus subtilis Involved in Endospore Cortex Maturation

摘要: Bacterial endospores are characterized by their extreme dormancy and high-level resistance to a range of stresses, in particular heat (7). The specialized spore structure determines properties, with the dehydrated core being crucial for resistance. cell wall peptidoglycan, known as cortex, is essential maintenance core, resistance, cortex has unique, spore-specific structure, recent analysis begun identify features important its role during differentiation reveal components responsible synthesis, modification sporulation, hydrolysis germination (1, 2). Spore an extremely low level cross-linking, which 15). A unique feature dormant presence muramic acid δ-lactam residues. This specific germination, because putative germination-specific lytic enzymes SleB CwlJ, degradation, require substrate recognition, since lacking this unable be hydrolyzed (2). During maturation, sporulation-specific amidase, CwlD, recently described polysaccharide deacetylase, PdaA, formation characteristic residues bacterial 8, Although cwlD or pdaA mutants double mutant can produce resistant endospores, no observed spores do not outgrow 2, 16, 18). final that about 25% side chains substituted single l-alanine 17). These may formed action l-Ala-d-Glu endopeptidase on nascent stem peptides. enzyme l-Ala have up now been unknown, peptidoglycan modification. In paper, we describe novel hydrolase, LytH (formerly YunA), required production cortex.