Interaction of the intermembrane space domain of Tim23 with mitochondrial membranes [Protein Structure and Folding]

October 27th, 2014 by Bajaj, R., Munari, F., Becker, S., Zweckstetter, M.

Tim23 mediates protein translocation into mitochondria. Although being inserted into the inner membrane, the dynamic association of its intermembrane space domain (IMS) with the outer membrane promotes protein import. However, little is known about the molecular basis of this interaction. Here, we demonstrate that the IMS domain of Tim23 tightly associates with both IMM- and OMM-like membranes through a hydrophobic anchor at its N-terminus. The structure of membrane-bound Tim23IMS is highly dynamic, allowing recognition of both the incoming presequence and other translocase components at the translocation contact. Cardiolipin enhances Tim23′s membrane attachment, suggesting that cardiolipin can influence preprotein import.