2MJJ: A Tetrahelical Dna Fold Adopted By Alternating Ggg And Gcg Tracts

DNA can form diverse higher-order structures, whose details are greatly dependent on nucleotide sequence. G-rich sequences containing four or more repeats of three guanines are expected to form G-quadruplexes. Here we show that DNA sequences with GGGAGCG repeats found in the regulatory region of the PLEKHG3 gene are capable of forming tetrahelical DNA structures that are distinct from G-quadruplexes. The d(GGGAGCGAGGGAGCG) sequence, VK1, forms a dimer. Two VK1 sequences connected by an adenine residue, VK2, fold into a monomer, which shares identical structural characteristics with the VK1 fold. Their four-stranded architectures are stabilized by four G-C, four G-A and six G-G base pairs. No G-quartets or Hoogsteen-type hydrogen-bonded guanine residues are present and the overall topology is conserved in the presence of Li(+), Na(+), K(+) and NH4(+) ions. Unique structural features include two edgewise loops on each side of the structure stabilized by three G-G base pairs in N1-carbonyl symmetric geometry.
PDB ID: 2MJJDownload
MMDB ID: 125931
PDB Deposition Date: 2014/1/10
Updated in MMDB: 2016/05
Experimental Method:
solution nmr
Biological Unit for 2MJJ: dimeric; determined by author
Molecular Components in 2MJJ
Label Count Molecule
Nucleotide(1 molecule)
Molecule annotation
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