4F55

Crystal Structure of the Catalytic Domain of the Bacillus cereus SleB Protein

Summary for 4F55

• Entry DOI: 10.2210/pdb4f55/pdb
• Descriptor: Spore cortex-lytic enzyme, PHOSPHATE ION (3 entities in total)
• Functional Keywords: hydrolase, lytic transglycosylase
• Biological source: Bacillus cereus
• Cellular location: Forespore : P0A3V0
• Total number of polymer chains: 1
• Total formula weight: 14191.56

Authors

Hao, B. (deposition date: 2012-05-11, release date: 2012-07-11, Last modification date: 2024-02-28)

Primary citation

Li, Y.,Jin, K.,Setlow, B.,Setlow, P.,Hao, B.
Crystal Structure of the Catalytic Domain of the Bacillus cereus SleB Protein, Important in Cortex Peptidoglycan Degradation during Spore Germination.
J.Bacteriol., 194:4537-4545, 2012

PubMed Abstract: The SleB protein is one of two redundant cortex-lytic enzymes (CLEs) that initiate the degradation of cortex peptidoglycan (PG), a process essential for germination of spores of Bacillus species, including Bacillus anthracis. SleB has been characterized as a soluble lytic transglycosylase that specifically recognizes spore cortex PG and catalyzes the cleavage of glycosidic bonds between N-acetylmuramic acid (NAM) and N-acetylglucosamine residues with concomitant formation of a 1,6-anhydro bond in the NAM residue. We found that like the full-length Bacillus cereus SleB, the catalytic C-terminal domain (SleB(C)) exhibited high degradative activity on cortex PG in vitro, although SleB's N-terminal domain, thought to bind PG, was inactive. The 1.85-Å crystal structure of SleB(C) reveals an ellipsoid molecule with two distinct domains dominated by either α helices or β strands. The overall fold of SleB closely resembles that of the catalytic domain of the family 1 lytic transglycosylases but with a completely different topological arrangement. Structural analysis shows that an invariant Glu157 of SleB is in a position equivalent to that of the catalytic glutamate in other lytic transglycosylases. Indeed, SleB bearing a Glu157-to-Gln mutation lost its cortex degradative activity completely. In addition, the other redundant CLE (called CwlJ) in Bacillus species likely has a three-dimensional structure similar to that of SleB, including the invariant putative catalytic Glu residue. SleB and CwlJ may offer novel targets for the development of anti-spore agents.

PubMed: 22730118
DOI: 10.1128/JB.00877-12

Experimental method

X-RAY DIFFRACTION (1.85 Å)