Question

Explain the roles of the Matrix Targeting Signal, the protein translocases involved in protein import, how ATP and membrane potential play a role in Protein....

Explain the mechanism by which a nuclear -encoded precursor protein is important to the inner membrane of the mitochondria?

Answer 1

Targeting signals are the pieces of information, which facilitate the cellular transport of various molecules to correctly transport the proteins into and out of the cell. Matrix targeting signal is one such signal, that facilitate the movement of proteins into and out of the matrix of the mitochondrion. The signal sequences are both necessary and sufficient for import of the proteins that contain them.

Protein translocases are the protein complexes present in the outer membrane of the mitochondrial membrane of the mitochondrion. Protein translocases allow the movement of proteins through it, and into the intermembrane space of the mitochondrion.The TOM complex functions across the outer membrane.

ATP hydrolysis is needed to supply the needed energy for the import of proteins into the mitochondrion, because the directional transport requires energy.

The mitochondrial protein import is fueled by ATP hydrolysis at outside the mitochondrion and inside the matrix. Apart from ATP hydrolysis, the electrochemical proton gradient across the inner mitochondrial membrane also is used as another energy source.

Most of the mitochondrial proteins are encoded by nuclear genes and then synthesized as the precursors on the cytosolic ribosomes.