Porin B is a porin from Corynebacterium glutamicum which allows the exchange of material across the mycolic acid layer which is the protective nonpolar barrier. Porin B has an alpha helical core structure consisting of four alpha-helices surrounding a nonpolar interior. There is a disulphide bridge between helices 1 and 4 to form a stable covalently bound ring. The channel of PorB is oligomeric.
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