Selectively Identifying Exposed-over-Unexposed C-C+ Pairs in Human Telomeric i-Motif Structures with Length-Dependent Polymorphism.
Anal Chem
; 94(43): 14994-15001, 2022 11 01.
Article
em En
| MEDLINE
| ID: mdl-36263663
ABSTRACT
The i-motif structure (iM) has attracted much attention, because of its in vivo bioactivity and wide in vitro applications such as DNA-based switches. Herein, the length-dependent folding of cytosine-rich repeats of the human telomeric 5'-(CCCTAA)n-1CCC-3' (iM-n, where n = 2-8) was fully explored. We found that iM-4, iM-5, and iM-8 mainly form the intramolecular monomer iM structures, while a tetramolecular structure populates only for iM-3. However, iM-6 and iM-7 have the potential to fold as well into the dimeric iM structures besides the monomer ones. The natural hypericin (Hyp) was used as the polymorphism-selective probe to recognize the iM structures. Interestingly, only iM-3, iM-6, and iM-7 can efficiently switch on the Hyp fluorescence by specifically binding with the outmost C-C+ base pairs that are exposed directly to solution. However, other iM structures that fold in a way with a coverage of the outmost C-C+ pairs by loop sequences are totally unavailable for the Hyp binding. Theoretical modeling indicates that adaptive π-π and cation-π interactions contribute to the Hyp recognition toward the exposed C-C+ pairs. This specific iM recognition can be boosted by a photocatalytic DNAzyme construct. Our work provides a reliable fluorescence method to selectively explore the polymorphism of iM structures.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
DNA
/
Telômero
Limite:
Humans
Idioma:
En
Revista:
Anal Chem
Ano de publicação:
2022
Tipo de documento:
Article