Intra- and interloop interactions in the folded G quartet structure of Oxytricha telomeric sequence.
Indian J Biochem Biophys
;
1995 Dec; 32(6): 385-90
Article
in English
| IMSEAR
| ID: sea-27654
ABSTRACT
The antiparallel intramolecular G quartet structure for the 3.5 copy Oxytricha telomeric sequence d(G4T4)3G4 has been established using a combination of spectroscopic and chemical probing methods. In the presence of Na+ ions, this sequence exhibits a circular dichroism spectrum with a positive band at 295 nm and a negative band around 265 nm, characteristic of an antiparallel G quartet structure. Further, we show that d(G4T4)3G4 adopts an antiparallel intramolecular G quartet structure even in K+ unlike d(G4T4G4). KMnO4 probing experiments indicated the existence of intra and interloop interactions in the Na+ induced structure. We have found that K+ not only increases the thermal stability of G quartet structure but also binds to the loop region and disrupts stacking and interloop interactions. Biological consequences of such cation-dependent conformational micro-heterogeneity in the loop region of G quartet structures is also discussed.
Full text:
Available
Index:
IMSEAR (South-East Asia)
Main subject:
Molecular Sequence Data
/
Base Sequence
/
Telomere
/
Oxytricha
/
Guanine
/
Animals
/
Nucleic Acid Conformation
Language:
English
Journal:
Indian J Biochem Biophys
Year:
1995
Type:
Article
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