Structure of the Trichomonas vaginalis Myb3 DNA-binding domain bound to a promoter sequence reveals a unique C-terminal β-hairpin conformation

Shu Yi Wei, Yuan Chao Lou, Jia Yin Tsai, Meng Ru Ho, Chun Chi Chou, M. Rajasekaran, Hong Ming Hsu, Jung Hsiang Tai, Chwan Deng Hsiao, Chinpan Chen

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Trichomonas vaginalis Myb3 transcription factor (tvMyb3) recognizes the MRE-1 promoter sequence and regulates ap65-1 gene, which encodes a hydrogenosomal malic enzyme that may play a role in the cytoadherence of the parasite. Here, we identified tvMyb353-180 as the essential fragment for DNA recognition and report the crystal structure of tvMyb353-180 bound to MRE-1 DNA. The N-terminal fragment adopts the classical conformation of an Myb DNA-binding domain, with the third helices of R2 and R3 motifs intercalating in the major groove of DNA. The C-terminal extension forms a β-hairpin followed by a flexible tail, which is stabilized by several interactions with the R3 motif and is not observed in other Myb proteins. Interestingly, this unique C-terminal fragment does not stably connect with DNA in the complex structure but is involved in DNA binding, as demonstrated by NMR chemical shift perturbation, 1H- 15N heteronuclear-nuclear Overhauser effect and intermolecular paramagnetic relaxation enhancement. Site-directed mutagenesis also revealed that this C-terminal fragment is crucial for DNA binding, especially the residue Arg 153 and the fragment K 170KRK 173. We provide a structural basis for MRE-1 DNA recognition and suggest a possible post-translational regulation of tvMyb3 protein.

Original languageEnglish (US)
Pages (from-to)449-460
Number of pages12
JournalNucleic acids research
Volume40
Issue number1
DOIs
StatePublished - Jan 2012
Externally publishedYes

ASJC Scopus subject areas

  • Genetics

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