The G-rich strand of human telomeric DNA can fold into a four-stranded structure called（G-quadruplex.）In this work

we studied the effect of flanking sequence on the thermal stability and the folding/unfolding kinetics of G-quadruplex formed by the core sequence G

3

(T

2

AG

3

)

3

of human telomeric DNA.We show that the introduction of flanking sequence greatly reduced the thermal stability of G-quadruplex as exhibited by decreased melting temperature(T

m

).On the other hand

the presence of flanking sequence also decreased the folding and unfolding rate constants(k

f

k

u

)

resulting in a slightly decreased folding equilibrium constant(K

F

).