Interactions of Mitochondrial Presequence Peptides with the Mitochondrial Outer Membrane Preprotein Translocase TOM

TOM protein-conducting channels serve as the main entry sites into mitochondria for virtually all mitochondrial proteins. When incorporated into lipid bilayers, they form large, relatively nonspecific ion channels that are blocked by peptides derived from mitochondrial precursor proteins. Using sing...

Full description

Saved in:
Bibliographic Details
Published in:Biophysical journal 2010-08, Vol.99 (3), p.774-781
Main Authors: Romero-Ruiz, Mercedes, Mahendran, Kozhinjampara R., Eckert, Reiner, Winterhalter, Mathias, Nussberger, Stephan
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Biochemistry
Biophysics
Blockage
Carrier Proteins - metabolism
Channels
Channels and Transporters
Ion Channel Gating
Ion channels
Ion Channels - metabolism
Kinetics
Lipids
Membrane Potentials - physiology
Membranes
Mitochondria
Mitochondria - enzymology
Mitochondria - ultrastructure
Mitochondrial Membranes - enzymology
Mitochondrial Membranes - metabolism
Mitochondrial Membranes - ultrastructure
Mitochondrial Proteins - metabolism
Models, Biological
Molecular Sequence Data
Neurospora crassa - metabolism
Neurospora crassa - ultrastructure
Peptides
Peptides - chemistry
Peptides - metabolism
Precursors
Protein Binding
Protein Precursors - metabolism
Protein Sorting Signals
Proteins
Recording
Substrate Specificity
Time Factors
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:TOM protein-conducting channels serve as the main entry sites into mitochondria for virtually all mitochondrial proteins. When incorporated into lipid bilayers, they form large, relatively nonspecific ion channels that are blocked by peptides derived from mitochondrial precursor proteins. Using single-channel electrical recordings, we analyzed the interactions of mitochondrial presequence peptides with single TOM pores. The largest conductance state of the translocon represents the likely protein-conducting conformation of the channel. The frequency (but not the duration) of the polypeptide-induced blockage is strongly modulated by the substrate concentration. Structural differences between substrates are reflected in characteristic blockage frequencies and duration of blockage. To our knowledge, this study provides first quantitative data regarding the kinetics of polypeptide interaction with the mitochondrial TOM machinery.
ISSN:0006-3495
1542-0086
DOI:10.1016/j.bpj.2010.05.010