Monomeric active forms of all members of the TGF-β family (3 conserved intramolecular disulfide Linkages) contain a conserved cysteine residue that forms a disulfide bond links TGF-β monomers into functional homodimers

and heterodimers

TLS Online TPP Program

#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.

TLS Online TPP Program

#Id: 7913

#XL - Q Biochemistry

Matrix-targeting sequences

sequences for localizing proteins to mitochondria

TLS Online TPP Program

#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

TLS Online TPP Program

#Id: 7915

#XL - Q Biochemistry

Mitochondrial protein import requires: 

Tom proteins (Tom 20/22/70)

General import pore (Tom40)

Tim proteins (Tim23/17)

TLS Online TPP Program

#Id: 7916

#XL - Q Biochemistry

Energy inputs are needed to Import proteins into mitochondria

Chaperone proteins (Hsp70& Hsp90)

An H+ electrochemical gradient, or proton-motive force

TLS Online TPP Program

#Id: 7917

#XL - Q Biochemistry

Brown Adipose Tissue

is brown because of the presence of large numbers of mitochondria (high concentrations of cytochromes), with heme groups that are strong absorbers of visible