Positively charged residues, the helical conformation and the structural flexibility of the leader sequence of pALDH are important for recognition by hTom20.
Tom20, a mitochondrial outer membrane receptor necessary for protein translocation, was found to interact specifically with mitochondrial preproteins. The interaction of proteins containing an N-terminal matrix targeting signal was enhanced in an hydrophobic environment and the dependence of this interaction on the alpha helical conformation of the presequence was postulated. In order to test this hypothesis and to gain insights about the features of a matrix targeting signal necessary to be recognized by the receptor machinery including Tom20, the interaction of pALDH and signal sequence mutants to Tom20 in the absence and presence of a hydrophobic environment was investigated. Here we present evidence to show that in a hydrophobic environment the interaction between Tom20 and the leader sequence is strongly dependent on the positive charges within the signal sequence as well as on the flexibility of this signal.
Schleiff
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Department of Biochemistry, McGill University, Montreal, Que., Canada.
Heard
T S
TS
Weiner
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H
D020121:5' Untranslated Regions / Q000737:chemistry / Q000378:metabolism*; D000426:Alcohol Dehydrogenase / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D005982:Glutathione Transferase / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008081:Liposomes / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction
D020121:5' Untranslated Regions; D008081:Liposomes; D008565:Membrane Proteins; D011994:Recombinant Proteins; D000426:Alcohol Dehydrogenase; D005982:Glutathione Transferase