Cortical fragment-lytic enzyme (CFLE) is a peptidoglycan hydrolase involved in bacterial endospore germination. CFLE is expressed as an inactive preprotein (called SleB) in the forespore compartment of sporulating cells. SleB translocates across the forespore inner membrane and is deposited as a mature enzyme in the cortex layer of the spore. As part of a sensory mechanism capable of initiating germination, CFLE degrades a spore-specific peptidoglycan constituent called muramic-acid delta-lactam that comprises the outer cortex. CFLE has a C-terminal glycosyl hydrolase family 18 (GH18) catalytic domain as well as two N-terminal LysM peptidoglycan-binding domains. In addition to SleB, this family includes YaaH, YdhD, and YvbX from Bacillus subtilis.

Copper amine oxidase N-terminal domain. Copper amine oxidases catalyze the oxidative deamination of primary amines to the corresponding aldehydes, while reducing molecular oxygen to hydrogen peroxide. These enzymes are dimers of identical subunits, each comprising four domains. The N-terminal domain, which is absent in some amine oxidases, consists of a five-stranded antiparallel beta sheet twisted around an alpha helix. The D1 domains from the two subunits comprise the 'stalk' of the mushroom-shaped dimer, and interact with each other but do not pack tightly against each other.

Spore germination protein YaaH [Cell cycle control, cell division, chromosome partitioning].

Glycosyl hydrolases family 18.

The GH18 (glycosyl hydrolase, family 18) type II chitinases hydrolyze chitin, an abundant polymer of beta-1,4-linked N-acetylglucosamine (GlcNAc) which is a major component of the cell wall of fungi and the exoskeleton of arthropods. Chitinases have been identified in viruses, bacteria, fungi, protozoan parasites, insects, and plants. The structure of the GH18 domain is an eight-stranded beta/alpha barrel with a pronounced active-site cleft at the C-terminal end of the beta-barrel. The GH18 family includes chitotriosidase, chitobiase, hevamine, zymocin-alpha, narbonin, SI-CLP (stabilin-1 interacting chitinase-like protein), IDGF (imaginal disc growth factor), CFLE (cortical fragment-lytic enzyme) spore hydrolase, the type III and type V plant chitinases, the endo-beta-N-acetylglucosaminidases, and the chitolectins. The GH85 (glycosyl hydrolase, family 85) ENGases (endo-beta-N-acetylglucosaminidases) are closely related to the GH18 chitinases and are included in this alignment model.

ChainA, Spore germination protein YaaH [Priestia megaterium QM B1551]

Thecrystal structure of a class V chitininase from Pseudomonas fluorescens Pf-5 [Pseudomonas protegens Pf-5]

ChainA, Putative sporulation-specific glycosylase ydhD [Bacillus subtilis subsp. subtilis str. 168],3CZ8_B Chain B, Putative sporulation-specific glycosylase ydhD [Bacillus subtilis subsp. subtilis str. 168]

Cortical fragment-lytic enzyme OS=Bacillus subtilis (strain 168) OX=224308 GN=sleL PE=1 SV=2

Putative sporulation-specific glycosylase YdhD OS=Bacillus subtilis (strain 168) OX=224308 GN=ydhD PE=1 SV=2