Alamethicin

Alamethicin is a channel-forming peptide antibiotic, produced by the fungus Trichoderma viride.

The peptide sequence is where Ac = acetyl, Phl = phenylalaninol, and Aib = 2-Aminoisobutyric acid.

In cell membranes, it forms voltage-dependent ion channels by aggregation of four to six molecules.

[2] Although there are several sequences of the alamethicin peptide accepted,[3] evidence suggests these all follow the general NRPS mechanism [4] with small variations at select amino acids.

[8] The growing chain is attached to the amino acid bearing PCP by the "condensation" (C) domain, followed by another round of the same reactions by the next module.

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The general mechanism of NRPS synthesis in alamethicin, showing the condensation of amino acid substrates from module to module. Ac=Acetyl Aib=aminoisobutyric acid. Module components: A= Adenylylation PCP= Peptidyl Carrier Protein C=Condensation
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A diagram of the individual modules and elongation of alamethicin biosynthesis. The growing peptide chain is shown for each module, ending in the cleavage of the thioester and generation of linear alamethicin. Ac=Acetyl Aib=Aminoisobutyric acid Pheol=Phenylalaninol. Module components: A=Adenylylation PCP= Peptidyl Carrier Protein C=Condensation