title: Exploration of the selective recognition of the G-quadruplex in the N-myc oncogene by electrospray ionization mass spectrometry.
abstract: BACKGROUND
  The N-myc gene is a member of the MYC family and its amplification is highly correlated with the pathophysiology of cancers. The G-rich sequence, d(AG3CG3AG3AG3A), in the first intron of N-myc can form a G-quadruplex structure. Small molecules binding to it with high affinity and selectivity may provide a potential approach to modulate the expression of the N-myc gene.
  
  
  METHODS
  Electrospray ionization (ESI) mass spectrometry was used to analyze the G-quadruplex formation of the d(AG3CG3AG3AG3A) sequence, and to evaluate the binding affinities and selectivities of natural small molecules with the N-myc G-quadruplex.
  
  
  RESULTS
  Enniatin B was found to have the highest binding affinity with this G-quadruplex within the 12 small molecules. Moreover, it also showed a biased selectivity toward the N-myc G-quadruplex compared with the other five G-quadruplexes derived from C-myc, Bcl2, Chl1, c-kit promoters and telomere G-rich sequences.
  
  
  CONCLUSIONS
  In this study, we found a natural small molecule, enniatin B, which could bind to the G-quadruplex of the d(AG3CG3AG3AG3A) sequence from the first intron of the N-myc gene with high affinity and selectivity, which may lead to a potential modulation of the N-myc gene.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
authors.forename: Fangyuan
authors.initials: F
authors.lastname: Li
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
authors.forename: Han
authors.initials: H
authors.lastname: Chen
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
authors.forename: Jiang
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
authors.forename: Gu
authors.initials: G
authors.lastname: Yuan
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D047630:Depsipeptides / Q000378:metabolism* / Q000494:pharmacology; D054856:G-Quadruplexes; D016259:Genes, myc; D006801:Humans; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods
chemical_list: D047630:Depsipeptides; C100264:enniatins