Solution structures of Myb DNA-binding domain and its complex with DNA.
The DNA-binding domain of Myb consists of three imperfect tandem repeats, each of which contains three conserved tryptophans. The solution structure of the third repeat was established by NMR; it includes three helices maintained by a hydrophobic core formed by three tryptophans, together with two histidines, and the second and third helices form a helix-turn-helix-related motif. Here, we report the whole structure of the DNA-binding domain, as determined by NMR. Each of the first and second repeats resembles the third one in structure, retaining three helices. As a whole, the DNA-binding domain contains an entirely unique structure, a triple helix-turn-helix-related motif. To determine the role of each repeat in DNA-binding, a 16-mer DNA duplex that is specifically recognized by Myb was synthesized and then its complex with the DNA-binding domain has been investigated by 3D-NMR. The interaction mode between the whole DNA-binding domain and the duplex has shown that the third helix in each repeat likely locates in the majour groove of DNA. It is suggested that the Myb DNA-binding domain wraps around the DNA duplex by fitting the triply repeated helix-turn-helix-related motifs in the majour groove.
Ogata
K
K
Graduate School of Integrated Science, Yokohama City University, Japan.
Kanai
H
H
Inoue
T
T
Sekikawa
A
A
Sasaki
M
M
Nagadoi
A
A
Sarai
A
A
Ishii
S
S
Nishimura
Y
Y
D001483:Base Sequence; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D018257:Helix-Loop-Helix Motifs; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011518:Proto-Oncogene Proteins / Q000737:chemistry* / Q000378:metabolism; D020598:Proto-Oncogene Proteins c-myb; D012996:Solutions
D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D020598:Proto-Oncogene Proteins c-myb; D012996:Solutions; D004247:DNA