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Medizin - Open Access LMU - Teil 07/22 Podcast
Role of ATP in mitochondrial protein import

Role of ATP in mitochondrial protein import

Medizin - Open Access LMU - Teil 07/22 vor 38 Jahren

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The role of nucleoside triphosphates (NTPs) in the import of porin
into the mitochondrial outer membrane was investigated with two
forms of the porin precursor: the in vitro synthesized biosynthetic
precursor (bs- porin) and a water-soluble form of porin (ws-porin)
obtained by subjecting the membrane-derived porin to an acid-base
treatment (exposure to trichloroacetic acid, followed by alkali and
rapid neutralization). The import of ws-porin into mitochondria did
not require NTPs, whereas the import of bs-porin required NTPs. In
other characteristics, such as binding to a specific receptor
protein on the mitochondrial surface, two-step insertion into the
outer membrane, and formation of specific membrane channels,
ws-porin was indistinguishable from bs-porin. Thus, the acid-base
treatment applied in the preparation of ws-porin can substitute for
the NTP-requiring step in mitochondrial protein import. We conclude
that NTPs are required for unfolding mitochondrial precursor
proteins ("translocation competent folding").