SAM Complex Assembly of Mitochondrial Porins

Mitochondrial porins are beta-barrel proteins that are built into the outer membrane with help from the TOM and SAM systems. Porin precursors first move through the TOM complex into the intermembrane space. They then bind TIM chaperones, which guide them to the Sorting and Assembly Machinery, or SAM, complex on the outer mit...

There are three models that describe the insertion of porins into the outer mitochondrial membrane.

The first model suggests that the beta-barrel precursors are folded outside the SAM channel and simultaneously inserted into the outer membrane.

The second model proposes that the unfolded precursor passes through the SAM channel. Af...