| Type: | Family | Name: | Capsule biosynthesis protein CapB |
| Description: | Bacillus spp. are Gram-positive aerobic rods that are able to form endo- spores that allow them to survive in almost any environment. The manydifferent species exhibit a wide variation of physiological abilities, their spores being resistant, for example, to heat, cold, disinfection andradiation. However, the spores require oxygen to sporulate, which has important consequences. Of particular interest to researchers areBacillus anthracis, Bacillus cereusand Bacillus subtilis, all extremely pathogenic microbes that owe their virulence to the exotoxins they secrete and to the extracellular polypeptide and polysaccharide capsules that protect them from the host immune system [].The capsule of B. anthracis is composed of poly-D-glutamic acid, which is the principal non-toxin virulence factor of the bacterium []. It is believed to inhibit host defence via evasion of macrophages, and, in conjunction with the lethal anthrax and oedema toxin, spreads rapidly through the host. Three virulence plasmid-associated enzymes are responsible for the synthesis of the capsule, termed CapA, CapB and CapC. The "cap" region is found on the B. anthracis pX02 plasmid, and is transcriptionally regulated by cytoplasmic levels of bicarbonate [].Further analysis of the two major B. anthracis virulence plasmids (pX02 and pX01) has revealed that transcription and translation of the cap synthesisenzymes in pX02 is essential for activation of pX01, which carries the pag, gd; lef and cya exotoxin genes []. It is believed that, together with CapB and gd; CapC, CapA forms a polyglutamyl sythetase complex to produce the mature polyglutamate capsule. Moreover, the capB gene is the first cistron in the cap region, and regulates the expression of all three capsule synthesis genes. | Short Name: | Capsule_biosynth_CapB |
