The N‐terminal half of a mitochondrial presequence peptide inserts into cardiolipin‐containing membranes Consequences for the action of a transmembrane potential

[摘要]

The orientation of a mitochondrial presequence peptide, associated with anionic lipid-containing model membranes, was investigated. The peptide inserts with its N-terminal α-helical part into cardiolipin (CL) monolayers so that the N-terminal 14 residues are protected from proteinase K. In phosphatidylglycerol (PG) monolayers the inserted peptide was fully accessible to the protease. A consequence of the different orientations of the peptide was that membrane potential-dependent protection from trypsin was much faster for the peptide bound to PG-containing vesicles compared to CL-containing membranes, suggesting that in the mitochondrial protein import process other components of the import apparatus are involved in the efficient potential-driven translocation of presequences across the inner mitochondrial membrane.

[学科分类] 生物化学/生物物理

[关键词] Mitochondrial presequence;Peptide topology;Monolayer insertion;Amino acid sequence analysis;Membrane potential;ATR;attenuated total reflection;CL;cardiolipin;DOPC;1;2-dioleoyl-sn-glycero-3-phosphocholine;DOPG;1;2-dioleoyl-sn-glycero-3-phosphoglycerol;egg PC;phosphatidylcholine from egg yolk;EDTA;(ethylenedinitrilo)tetraacetic acid;FTIR;Fourier transform infrared;HEPES;N-(2-hydroxyethyl)piperazine-N′-2-ethanesulfonic acid;πi;initial surface pressure;Δπ;surface pressure increase;Δψ;membrane potential;LUVs;large unilamellar vesicles;p25;peptide corresponding to the presequence of cytochrone oxidase subunit IV;p25NBD;p25 labeled with 7-nitro-2;1;3-benzoxadiazol-4-yl;PK;proteinase K;POPG;1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol