Ligand binding depends on: 

Multiple weak, noncovalent forces

Molecular complementarity

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#Id: 7909

#XL - Q Biochemistry

Membrane contact sites (MCSs)

Mitochondria establish MCSs with many other organelles, including ER, lysosomes, peroxisomes, the plasma membrane, the Golgi, endosomes, and even lipid droplets.

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#Id: 7910

#XL - Q Biochemistry

Mitochondria-associated membranes (MAMs)

The portions of the ER membranes that form special contact regions with the mitochondria.

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#Id: 7911

#XL - Q Biochemistry

MCSs also serve as interfaces for the transfer of ions (Ca+2 ) and small molecules (glycerophospholipids) between the ER and mitochondria.

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#Id: 7912

#XL - Q Biochemistry

The majority of proteins located in mitochondria are not encoded by mtDNA, they are encoded by genes in the nucleus and are imported into the mitochondria after their synthesis in the cytosol.

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#Id: 7913

#XL - Q Biochemistry

Matrix-targeting sequences

sequences for localizing proteins to mitochondria

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#Id: 7914

#XL - Q Biochemistry

Matrix-targeting sequences

Located at the N-terminus

Usually 20–50 amino acids in length

Rich in hydrophobic amino acids, positively charged basic amino acids (arginine & lysine), and hydroxylated ones (serine and threonine)

Amphipathicity of matrix-targeting sequences is critical to their function