Mitochondrial protein, binding

Incorporation of labeled amino acids into proteins certainly does not prove that protein synthesis takes place. In fact, denatured mitochondrial proteins bind considerable amounts of radioactively labeled amino acids and specific binding of amino acids ( transpeptidation ) to mitochondrial protein-lipid structures has been reported (Hochberg et al., 1972). Thus credit for measuring mitochondrial protein synthesis can only be given if the data include reasonable zero time controls and if the amino acid incorporation reaction is sensitive to chloramphenicol or to another suitable antibiotics known to inhibit mitochondrial protein synthesis. 

BH3 domain) of the BH3-only proteins binds to other Bcl-2 family members thereby influencing their conformation. This interaction facilitates the release of cytochrome C and other mitochondrial proteins from the intermembrane space of mitochondria. Despite much effort the exact biochemical mechanism which governs this release is not yet fully understood. The release of cytochrome C facilitates the formation of the apoptosome, the second platform for apoptosis initiation besides the DISC. At the apoptosome which is also a multi-protein complex the initiator caspase-9 is activated. At this point the two pathways converge. 

Based on the intrinsic mitochondriotropism of dequalinium and its unique self-assembly behavior, we have developed a strategy for direct mitochondrial transfection (47-49), which involves the transport of a DNA-mitochondrial leader sequence (MLS) peptide conjugate to mitochondria using DQAsomes, the liberation of this conjugate from the cationic vector upon contact with the mitochondrial outer membrane followed by DNA uptake via the mitochondrial protein import machinery. We have demonstrated that DQAsomes fulfill all essential prerequisites for a mitochondria-specific DNA delivery system they bind and condense pDNA (24), protect it from... 

Boerner JL, Demory ML, Silva C et al. Phosphorylation of Y845 on the epidermal growth factor receptor mediates binding to the mitochondrial protein cytochrome c oxidase subunit II. Mol Cell Biol 2004 24 7059-7071. 

Of course, the stress proteins themselves may be targets for reactive metabolites or ROS, in which case the protective ability may be lost. For example, a reactive metabolite(s) of halo thane, the hepatotoxic anesthetic drug (see chap. 7), binds to hsp60 and hsp70, which are mainly mitochondrial proteins. 

Landin JS, Cohen SD, Khairallah EA. Identification of a 54kDa mitochondrial acetaminophen binding protein as aldehyde dehydrogenase. Toxicol App Pharmacol 1996 141 299. 

Aconitase exists as both mitochondrial and cytosolic isoenzyme forms of similar structure. However, the cytosolic isoenzyme has a second function. In its apoenzyme form, which lacks the iron-sulfur cluster, it acts as the much-studied iron regulatory factor, or iron-responsive element binding protein (IRE-BP). This protein binds to a specific stem-loop structure in the messenger RNA for proteins involved in iron transport and storage (Chapter 28).86/9°... 

In addition to finding small organic molecules that bind to a protein, covalent capture methods can identify peptides that interact with proteins. Kohda and colleagues used this approach to study the mitochondrial protein Tom20, an import receptor that recognizes an epitope on proteins targeted for the mitochondria.1301 Previous work had characterized this epitope as a five-residue peptide that assumes an amphiphilic helical conformation, and coarse sequence preferences had been worked out. However, Tom20 has both low affinity... 

A mitochondrial T3-binding protein has been detected [11] but its function and physiological relevance remain largely unknown. Recently, it has been shown that a mitochondrial enzyme, adenine nucleotide transferase, exhibits high affinity binding of T3 [12]. 

Anti-apoptotic Bcl-2 Family Proteins Are Targets of BPB-only Proteins and Inhibitors of Bax/Bak. Bcl-2, Bcl-xL, Bcl-w, Al, and Mcl-1 are anti-apoptotic Bcl-2 family proteins and are localized in the cytosol and on the cytoplasmic face of the mitochondrial outer membrane. In healthy cells they sequester Bax/Bak proteins, presumably through direct association. When BH3-only proteins bind to Bcl-2... 

It has been shown that mutant Htt binds to CBP and p53. The latter protein regulates transcription of various mitochondrial proteins (Sawa, 2001). 

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