The sea urchin mitochondrial transcription factor A binds and bends DNA efficiently despite its unusually short C-terminal tail

Mitochondrial transcription factor A (TFAM) is a key component for the protection and transcription of the mitochondrial genome. TFAM belongs to the high mobility group (HMG) box family of DNA binding proteins that are able to bind to and bend DNA. Human TFAM (huTFAM) contains two HMG box domains se...

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Bibliographic Details
Published in:Mitochondrion 2016-07, Vol.29, p.1-6
Main Authors: Malarkey, Christopher S, Lionetti, Claudia, Deceglie, Stefania, Roberti, Marina, Churchill, Mair E A, Cantatore, Palmiro, Loguercio Polosa, Paola
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Animals
DNA Mutational Analysis
DNA, Mitochondrial - metabolism
Echinoidea
Fluorescence Resonance Energy Transfer
Mitochondrial Proteins - genetics
Mitochondrial Proteins - metabolism
Molecular Sequence Data
Mutagenesis, Site-Directed
Paracentrotus lividus
Protein Binding
Sea Urchins - metabolism
Transcription Factors - genetics
Transcription Factors - metabolism
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Summary:Mitochondrial transcription factor A (TFAM) is a key component for the protection and transcription of the mitochondrial genome. TFAM belongs to the high mobility group (HMG) box family of DNA binding proteins that are able to bind to and bend DNA. Human TFAM (huTFAM) contains two HMG box domains separated by a linker region, and a 26 amino acid C-terminal tail distal to the second HMG box. Previous studies on huTFAM have shown that requisites for proper DNA bending and specific binding to the mitochondrial genome are specific intercalating residues and the C-terminal tail. We have characterized TFAM from the sea urchin Paracentrotus lividus (suTFAM). Differently from human, suTFAM contains a short 9 amino acid C-terminal tail, yet it still has the ability to specifically bind to mtDNA. To provide information on the mode of binding of the protein we used fluorescence resonance energy transfer (FRET) assays and found that, in spite of the absence of a canonical C-terminal tail, suTFAM distorts DNA at a great extent and recognizes specific target with high affinity. Site directed mutagenesis showed that the two Phe residues placed in corresponding position of the two intercalating Leu of huTFAM are responsible for the strong bending and the great binding affinity of suTFAM.
ISSN:1567-7249
1872-8278
DOI:10.1016/j.mito.2016.04.004