Pertussis toxin they are formed from two subunits. The "A" subunit possesses enzyme activity, and is transferred to the host cell following a conformational change in the membrane-bound transport "B" subunit. Pertussis toxin is an exotoxin with six subunits (named "S1" through "S5"—each complex contains two copies of "S4"). The subunits are arranged in "A-B" structure: the "A" component is enzymatically active and is formed from the S1 subunit, while the "B" component is the receptor-binding portion and is made up of subunits S2–S5. The subunits are encoded by "ptx" genes encoded on a large PT operon that also includes additional genes
Byne's disease high humidity can also affect pyrite (or its more reactive polymorph marcasite) (iron sulphide) fossils in a somewhat similar condition, which is known as pyrite disease. The iron sulfide can react with water and oxygen to form iron sulfates and sulfuric acid, which then can produce Bynesian decay. Byne's disease Byne's disease, more accurately known as Bynesian decay, is a peculiar and permanently damaging condition (resulting from an ongoing chemical reaction) which often attacks mollusk shells that are in storage or on display for long periods of time. Bynesian decay is a form of efflorescence of salts formed by the