Lon (or La) is a soluble, homooligomerie ATP-dependent protease. Mass determination and cryoelectron microscopy of pure mitochondrial Lon from Saccharomyces cerevisiae identify Lon as a flexible ring-shaped heptamer. In the presence of ATP or 5'-adenylylimidodiphosphate, most of the rings are symmetric and resemble other ATP-driven machines that mediate folding and degradation of proteins. In the absence of nucleotides, most of the rings are distorted, with two adjacent subunits forming leg-like protrusions. These results suggest that asymmetric conformational changes serve to power processive unfolding and translocation of substrates to the active site of the Lon protease.
|Original language||English (US)|
|Number of pages||4|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Jun 8 1999|
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