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Unusual structures of TTTA repeats in icaC gene of Staphylococcus aureus
Author(s) -
Guo Pei,
Lam Sik Lok
Publication year - 2015
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2015.04.031
Subject(s) - dumbbell , direct repeat , gene , staphylococcus aureus , dna , coding region , sequence (biology) , genetics , biology , bacteria , base sequence , physiology
One and two TTTA repeat expansions have been found in the coding region of icaC gene of Staphylococcus aureus variants which influence the expression of IcaC protein and alter the phenotype. Yet, the mechanism of these small‐size TTTA repeat expansions remains unclear. In this study, we performed high‐resolution nuclear magnetic resonance spectroscopic studies on TTTA repeats. Our results show that a DNA sequence containing three TTTA repeats can fold into dumbbell structures with a 3′ or 5′‐overhang. Exchange of these dumbbells makes the sequence behave like a 2‐nt TT mini‐loop at 25 °C. The occurrence of these mini‐loop and dumbbell structures in the nascent strand during DNA replication provides possible mechanistic pathways which account for one and two repeat expansions.