Bacillus cereus non-hemolytic enterotoxin (Nhe) component A (NheA), and similar proteins
This model contains Bacillus cereus tripartite non-hemolytic enterotoxin (Nhe) component A (NheA), a member of the cytolysin A (ClyA) family of alpha pore-forming toxins (alpha-PFTs). Non-hemolytic enterotoxin (Nhe), despite its name, is hemolytic and able to lyse erythrocytes from various mammalian organisms. It consists of three proteins, NheA, NheB and NheC, encoded by one operon containing three genes nheA, nheB and nheC, respectively. Separately, these three proteins show no toxicity; maximal activity is seen only when all three components are presented. The NheB and NheC components are able to bind to cell membranes while NheA is not; NheC primes the host cell for the formation of ion permeable NheB/C pores. Binding of NheA to NheB/NheC is thought to be the final stage of pore formation. Structure of NheA shows an elongated, almost entirely alpha-helical protein with an enlarged "head" domain compared with other cytolysins, displaying on its surface an enlarged beta-tongue which is of amphipathic rather than hydrophobic nature. It has been proposed that NheA could even form beta-barrel pores.
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