Conserved hydrophobic amino acid residues in the N-terminal region of DnaA protein are involved in DnaA-DnaA interaction.
We previously reported that a leucine-zipper-like structure (I26, L33 and L40) located in the N-terminal region of DnaA is essential for the duplex opening at oriC by DnaA. In this study, we focused on three other conserved hydrophobic amino acid residues, L3, L10 and L17, and examined the function of DnaA proteins mutated in these amino acid residues. DnaA427 (L17S) and DnaA413 (L3S, L10S and L17S) were inactive for oriC DNA replication both in vitro and in vivo. Although these mutant DnaA proteins maintained their binding activities for both ATP and oriC, they were unable to induce the opening of duplex DNA at oriC. Glutathione-S-transferase (GST)-fused wild-type DnaA interacted with wild-type DnaA but not with DnaA427 and DnaA413. Based on these results, we propose that conserved hydrophobic amino acid residues in the N-terminal region of DnaA are involved in DnaA oligomerization, in which DnaA-DnaA interaction is required.
Mima
Shinji
S
Faculty of Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-naka, Okayama 700-8530, Japan.
Makise
Masaki
M
Koterasawa
Motohiro
M
Tsuchiya
Tomofusa
T
Mizushima
Tohru
T
D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D017434:Protein Structure, Tertiary
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C066312:DnaA protein, Bacteria; D000255:Adenosine Triphosphate; D004247:DNA