Disease relevance of exsF

• Spores of Bacillus anthracis, the causative agent of anthrax, are enclosed by a prominent loose fitting layer called the exosporium [1].
• The ExsA protein of Bacillus cereus is required for assembly of coat and exosporium onto the spore surface [2].
• Spores produced by bacilli are encased in a proteinaceous multilayered coat and, in some species (including Bacillus anthracis), further surrounded by a glycoprotein-containing exosporium [3].

High impact information on exsF

• In this study, we demonstrated that two O-linked oligosaccharides, a 715-Da tetrasaccharide and a 324-Da disaccharide, are released from spore- and exosporium-associated BclA by hydrazinolysis [1].
• We found that these spores survive and escape from macrophages, and that the bacterial metalloprotease InhA1, the major component of the exosporium, is essential for efficient spore release from macrophages [4].
• To date, the structural contribution of only one exosporium component, the collagen-like glycoprotein BclA, has been described [5].
• Although most of the exosporium genes are scattered on the genome, bclA and exsF are clustered in a region flanking the rhamnose biosynthesis operon; rhamnose is part of the sugar moiety of spore glycoproteins [6].
• In addition, transfer of the 98-MDa plasmid to Bacillus cereus resulted in transcipients that produced small inclusions enclosed within the exosporium, and the protein extracted from these inclusions reacted with antibody specific for enclosed inclusion protein of B. thuringiensis subsp. finitimus [7].

Anatomical context of exsF

• One inclusion was formed within the exosporium and remained with the spore after mother cell lysis [7].
• Electron micrographs of the DPA-less spores suspended in 2.2 M sucrose revealed a shrinkage of outer coats and exosporium membranes [8].

Associations of exsF with chemical compounds

• Seven proteins were identified in washed exosporium: alanine racemase, inosine hydrolase, ExsF, CotY, ExsY, CotB and a novel protein, named ExsK [9].
• When the spores were treated with 10% 2-mercaptoethanol, there was partial destruction of the exosporium as well as detachment of the filamentous appendages [10].
• The main components of both filamentous appendages and the exosporium were protein and their amino acid compositions were similar in point of a high content of glycine, alanine, threonine, valine, and acidic amino acids and a low content of basic and sulphur-containing amino acids [10].

Analytical, diagnostic and therapeutic context of exsF

• Electron microscopy revealed that the exsF mutant spores have defective exosporia [5].
• Here, using in vitro atomic force microscopy, we have directly visualized high-resolution native structures of bacterial endospores, including the exosporium and spore coats of four Bacillus species in air and water environments [11].
• Antibody D89 reacted with the exosporium and outer cortex of C. sporogenes spores in immunocytochemical localization studies but did not react with extracts of C. sporogenes or B. cereus spores in Western blotting [12].
• Analysis of the isolated exosporium by negative staining and digital image processing revealed a lattice structure belonging to the p 6 hexagonal space group with a repeat of 8.0 nm [13].

References