A pH-dependent bolt involving cytosine bases located in the lateral loops of antiparallel G-quadruplex structures within the SMARCA4 gene promotor.

ABSTRACT: Some lung and ovarian tumors are connected to the loss of expression of SMARCA4 gene. In its promoter region, a 44-nucleotides long guanine sequence prone to form G-quadruplex structures has been studied by means of spectroscopic techniques (circular dichroism, molecular absorption and nuclear magnetic resonance), size exclusion chromatography and multivariate analysis. The results have shown that the central 21-nucleotides long sequence comprising four guanine tracts of disparate length is able to fold into a pH-dependent ensemble of G-quadruplex structures. Based on acid-base titrations and melting experiments of wild and mutated sequences, the formation of a C·C⁺ base pair between cytosine bases present at the two lateral loops is shown to promote a reduction in conformationa

SUBMITTER: Benabou S 

PROVIDER: S-EPMC6825181 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature