8 research outputs found
Wei Hua's Four Parameter Potential Comments and Computation of Moleculer Constants \alpha_e and \omega_e x_e
The value of adjustable parameter and the four-parameter potential has been expressed in terms of molecular parameters and its significance
has been brought out. The potential so constructed, with derived from the
molecular parameters, has been applied to ten electronic states in addition to
the states studied by Wei Hua. Average mean deviation has been found to be 3.47
as compared to 6.93, 6.95 and 9.72 obtained from Levine2, Varshni and Morse
potentials, respectively. Also Dunham's method has been used to express
rotation-vibration interaction constant and anharmonocity
constant in terms of and other molecular constants.
These relations have been employed to determine these quantities for 37
electronic states. For , the average mean deviation is 7.2%
compared to 19.7% for Lippincott's potential which is known to be the best to
predict the values. Average mean deviation for turns out to
be 17.4% which is almost the same as found from Lippincott's potential
function.Comment: 19 RevTex Pages, 1 Ps figure, submitted to J. Phys.
Selective recognition of human telomeric G-quadruplex with designed peptide:Via hydrogen bonding followed by base stacking interactions
We described a novel synthetic peptide in which a glutamine residue binds through hydrogen bonding to a guanine-base and a trytophan residue intercalates with K(+) resulting in stabilization of a human telomeric G-quadruplex with high selectivity over its complementary c-rich strand and a double-stranded DNA and its complementary C-rich strand. This peptide offers great potential for cancer treatment by inhibiting the telomere extension by telomerase
Recognition and unfolding of human telomeric G-quadruplex by short peptide binding identified from the HRDC domain of BLM helicase
Research in recent decades has revealed that the guanine (G)-quadruplex secondary structure in DNA modulates a variety of cellular events that are mostly related to serious diseases. Systems capable of regulating DNA G-quadruplex structures would therefore be useful for the modulation of various cellular events to produce biological effects. A high specificity for recognition of telomeric G-quadruplex has been observed for BLM helicase. We identified peptides from the HRDC domain of BLM using a molecular docking approach with various available solutions and crystal structures of human telomeres and recently created a peptide library. Herein, we tested one peptide (BLM HRDC peptide) from the library and examined its interaction with human telomeric variant-1 (HTPu-var-1) to understand the basis of G4-protein interactions. Our circular dichroism (CD) data showed that HTPu-var-1 folded into an anti-parallel G-quadruplex, and the CD intensity significantly decreased upon increasing the peptide concentration. There was a significant decrease in hypochromicity due to the formation of G-quadruplex-peptide complex at 295 nm, which indicated the unfolding of structure due to the decrease in stacking interactions. The fluorescence data showed quenching upon titrating the peptide with HTPu-var-1-G4. Electrophoretic mobility shift assay confirmed the unfolding of the G4 structure. Cell viability was significantly reduced in the presence of the BLM peptide, with IC(50) values of 10.71 μM and 11.83 μM after 72 and 96 hours, respectively. These results confirmed that the selected peptide has the ability to bind to human telomeric G-quadruplex and unfold it. This is the first report in which a peptide was identified from the HRDC domain of the BLM G4-binding protein for the exploration of the G4-binding motif, which suggests a novel strategy to target G4 using natural key peptide segments