Publication Abstract from PubMed
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 tvMyb3(53-180) as the essential fragment for DNA recognition and report the crystal structure of tvMyb3(53-180) 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 beta-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, (1)H-(15)N 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(170)KRK(173). We provide a structural basis for MRE-1 DNA recognition and suggest a possible post-translational regulation of tvMyb3 protein.
Structure of the Trichomonas vaginalis Myb3 DNA-binding domain bound to a promoter sequence reveals a unique C-terminal beta-hairpin conformation.,Wei SY, Lou YC, Tsai JY, Ho MR, Chou CC, Rajasekaran M, Hsu HM, Tai JH, Hsiao CD, Chen C Nucleic Acids Res. 2012 Jan;40(1):449-60. Epub 2011 Sep 8. PMID:21908401[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
