Beta Barrel

The beta-barrel is an intergral transmembrane protein which functions as a membrane channel for molecules. The beta-barrel consists of a varying number of beta strands, from as few as 8 to as many as 22. This form of transmembrane protein is abundant in the outer membrane of mitochondria, choroplasts, and many bacteria in contrast to alpha-helix cell membrane protein which is frequently found in eukaryotic cell membranes .