Porins B and C are
cell wall channel-forming proteins from ''
Corynebacterium''. Porin B from ''Corynebacterium glutamicum'' (Brevibacterium flavum) allows the exchange of material across the mycolic acid layer, which is the protective nonpolar barrier. Porin B has an
alpha helical
The alpha helix (α-helix) is a common motif in the secondary structure of proteins and is a right hand-helix conformation in which every backbone N−H group hydrogen bonds to the backbone C=O group of the amino acid located four residues ear ...
core
structure consisting of four
alpha-helices
The alpha helix (α-helix) is a common motif in the secondary structure of proteins and is a right hand-helix conformation in which every backbone N−H group hydrogen bonds to the backbone C=O group of the amino acid located four residues ear ...
surrounding a nonpolar interior. There is a
disulfide bridge
In biochemistry, a disulfide (or disulphide in British English) refers to a functional group with the structure . The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In ...
between
helices
A helix () is a shape like a corkscrew or spiral staircase. It is a type of smooth space curve with tangent lines at a constant angle to a fixed axis. Helices are important in biology, as the DNA molecule is formed as two intertwined helices, ...
1 and 4 to form a stable covalently bound ring.
The channel of PorB is oligomeric.
References
{{InterPro content, IPR021114
Protein families