Isolation of intramitochondrial helical filaments appearing in outer compartment of mitochondria.
BACKGROUND
Packets of helical filaments have been observed in the outer compartment of occasional mitochondria in many cell types in a variety of animals. The composition and function of these intramitochondrial helical filaments (IMHF) are unknown.


METHODS
IMHF were induced in a hepatic mitochondria by administration of ethanol in the drinking water of rats. Hepatic mitochondria were isolated and ruptured by osmotic shock, releasing the IMHF. To purify these structures, the IMHF-containing supernatant was further fractionated by ammonium sulfate precipitation, a 50-60% solution of this reagent being the most effective in this regard. Isolated IMHF were examined by electron microscopy and were analyzed by SDS-PAGE.


RESULTS
Isolated IMHF closely resembled their in situ counterparts: they had a right-handed helical structure with a 16 nm pitch. SDS-PAGE analysis revealed that they contained three polypeptides with molecular weight of 135, 98, and 53 kD, respectively.


CONCLUSIONS
These observations will stand as a baseline for comparisons with IMHF that occur naturally or that are induced in other cell types by other kinds of experimental manipulation.
Sasaki
H
H
Division of Morphology, Jikei University School of Medicine, Japan.
Kurioka
S
S
Fukata
H
H
Ohoki
T
T
Arai
H
H
Suzuki
T
T
D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D006652:Histological Techniques; D008297:Male; D008854:Microscopy, Electron; D008930:Mitochondria, Liver / Q000648:ultrastructure*; D051381:Rats; D017207:Rats, Sprague-Dawley