2V1T

CRYSTAL STRUCTURE OF RAT TOM20-ALDH PRESEQUENCE COMPLEX

Replaces:  1WT4

Summary for 2V1T

• Entry DOI: 10.2210/pdb2v1t/pdb
• Related: 1OM2 1WT4 2CUV
• Descriptor: MITOCHONDRIAL IMPORT RECEPTOR SUBUNIT TOM20 HOMOLOG, ALDEHYDE DEHYDROGENASE (3 entities in total)
• Functional Keywords: outer membrane, transit peptide, phosphorylation, mitochondrion, transmembrane, oxidoreductase, protein transport, nad, membrane, transport
• Biological source: RATTUS NORVEGICUS (RAT); More
• Cellular location: Mitochondrion outer membrane; Single-pass membrane protein (Potential): Q62760; Mitochondrion matrix: P11884
• Total number of polymer chains: 4
• Total formula weight: 18741.28

Authors

Obita, T.,Igura, M.,Ose, T.,Endo, T.,Maenaka, K.,Kohda, D. (deposition date: 2007-05-29, release date: 2007-06-12, Last modification date: 2011-07-13)

Primary citation

Saitoh, T.,Igura, M.,Obita, T.,Ose, T.,Kojima, R.,Maenaka, K.,Endo, T.,Kohda, D.
Tom20 Recognizes Mitochondrial Presequences Through Dynamic Equilibrium Among Multiple Bound States.
Embo J., 26:4777-, 2007

PubMed Abstract: Most mitochondrial proteins are synthesized in the cytosol and imported into mitochondria. The N-terminal presequences of mitochondrial-precursor proteins contain a diverse consensus motif (phi chi chi phi phi, phi is hydrophobic and chi is any amino acid), which is recognized by the Tom20 protein on the mitochondrial surface. To reveal the structural basis of the broad selectivity of Tom20, the Tom20-presequence complex was crystallized. Tethering a presequence peptide to Tom20 through a disulfide bond was essential for crystallization. Unexpectedly, the two crystals with different linker designs provided unique relative orientations of the presequence with respect to Tom20, and neither configuration could fully account for the hydrophobic preference at the three hydrophobic positions of the consensus motif. We propose the existence of a dynamic equilibrium in solution among multiple states including the two bound states. In accordance, NMR 15N relaxation analyses suggested motion on a sub-millisecond timescale at the Tom20-presequence interface. We suggest that the dynamic, multiple-mode interaction is the molecular mechanism facilitating the broadly selective specificity of the Tom20 receptor toward diverse mitochondrial presequences.

PubMed: 17948058
DOI: 10.1038/SJ.EMBOJ.7601888

Experimental method

X-RAY DIFFRACTION (1.92 Å)