Anthrax Lethal Factor
From Proteopedia
IntroductionIntroductionPertussis Toxins (PT) is a protein-based exotoxin and major virulence factor produced by the bacterium Bordetella pertussis.[1] PT causes pertussis, which is also known at whooping cough and is highly contagious bacterial disease. The disease is caused by the bacterium colonizing the respiratory tract where it then establishes an infection.[2] This disease had been characterized by severe coughing that can last up to six weeks and in some countries lasting nearly 100 days.[2]It has been documented in some cases that PT can cause subconjunctival hemorrhages, rib fractures, hernias, fainting and vertebral artery dissection.[3] As of 2010, the worldwide incidence of whooping cough has been estimated to 48.5 million cases and nearly 295,000 deaths per year.[4] With that in mind, whooping cough can affect people of any age; however, before vaccines were available the disease was most common in infants and young children but now children are immunized and the high percentage of cases are seen among adolescents. StructureThe pertussis toxin has been characterized as being an AB toxin meaning that there are 2 subunits: A subunit possesses the enzyme activity and the B subunit possesses the receptor binding portion. PT in particular is an AB5 toxin consisting of a six-component protein complex, and the multiple subunits of the complex are not identical in composition.[1] With that in mind, this protein is a hexamer containing a catalytic (S1) subunit that is tightly associated with the pentameric cell-binding component (B-oligomer).[1] The S1 component is a single subunit while the B-oligomer is a pentamer composed of four types of subunits: , , two copies of , and .[1] The overall structure of PT . These subunits are encoded by ptx genes, which are encoded on a large PT operon that includes additional genes as well such as Pti genes. Together the PT and Pti proteins form the PT secretion complex and toxin itself.[5]
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