Showing papers by "Sudip Kundu published in 1999"
TL;DR: The computations reveal that the rigidity of a given DNA sequence is controlled by its ability to form cross-strand bifurcated hydrogen bonds between the successive base pairs.
Abstract: Persistence length and torsional rigidity for different B-DNA sequences have been calculated by analysing crystal structure database. The values of these parameters for mixed sequence DNA are in good agreement with those estimated by others. Persistence lengths for the homopolymeric sequences, namely poly(dA)·poly(dT) and poly(dG)·poly(dC), are significantly large compared to those of others as expected from the inability of these sequences to form nucleosome under normal conditions. The heteropolymeric sequences poly(dA-dC)·poly(dG-dT) and poly(dG-dC)·poly(dG-dC), on the other hand, have smaller persistence lengths. This implies larger flexibility of the d(AC)·d(GT), d(CA)·d(TG), d(GC)·d(GC) and d(CG)·d(CG) doublets, some of which constitute the genetic disease forming triplet repeats d(CTG)·d(CAG) and d(CGG)·d(CCG). Thus it is expected that these triplet repeat sequences are also flexible and wrap around the histone octamer efficiently. Persistence length calculations also indicate larger flexi...
26 citations
TL;DR: Numerical solutions are presented in the 2 dimensional case, while, in the more involved context of 3 dimensional shapes, the free energies of different, experimentally observed, shapes are compared.
Abstract: Shape equations for phospholipid vesicles including a spherical actin cortex are derived in 2 and 3 spatial dimensions. They arise from the condition of stationarity of the membrane free energy at fixed area and volume'. Numerical solutions are presented in the 2 dimensional case, while, in the more involved context of 3 dimensional shapes, the free energies of different, experimentally observed, shapes are compared. The relevance of the 2 dimensional study for the realistic case is also discussed. The theoretical results are analysed in the view of known experiments concerning shape changes of serf-assembled actin bilayer composite membranes.