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The MotA transcription factor from bacteriophage T4 contains a novel DNA‐binding domain: the ‘double wing’ motif
Author(s) -
Li Ning,
Sickmier E. Allen,
Zhang Rongguang,
Joachimiak Andrzej,
White Stephen W.
Publication year - 2002
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2002.02809.x
Subject(s) - biology , bacteriophage , dna , motif (music) , transcription factor , genetics , wing , computational biology , dna binding domain , transcription (linguistics) , dna binding protein , microbiology and biotechnology , gene , escherichia coli , physics , linguistics , acoustics , thermodynamics , philosophy
Summary MotA is a transcription factor from bacteriophage T4 that helps adapt the host Escherichia coli transcription apparatus to T4 middle promoters. We have determined the crystal structure of the C‐terminal DNA‐binding domain of MotA (MotCF) to 1.6 Å resolution using multiwavelength, anomalous diffraction methods. The structure reveals a novel DNA‐binding α/β motif that contains an exposed β‐sheet surface that mediates interactions with the DNA. Independent biochemical experiments have shown that MotCF binds to one surface of a single turn of DNA through interactions in adjacent major and minor grooves. We present a model of the interaction in which β‐ribbons at opposite corners of the six‐stranded β‐sheet pen‐etrate the DNA grooves, and call the motif a ‘double wing’ to emphasize similarities to the ‘winged‐helix’ motif. The model is consistent with data on how MotA functions at middle promoters, and provides an explanation for why MotA can form non‐specific multimers on DNA.