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Bending of the helical axis

Title CRYSTAL STRUCTURE OF BACILLUS DNA POLYMERASE I FRAGMENT COMP BASE PAIRS OF DUPLEX DNA.
PDB code 1L3S   (PDB summary)
NDB code PD0300 (NDB atlas)
Duplex length 9 base pairs
Protein DNA POLYMERASE I KLENOW FRAGMENT, Polymerase

Table 1.   Bending parameters determined with the program ARC_FIT.  
The curvilinear helical axis is calculated with CURVES, and bending of this axis is analysed with ARC_FIT. This program allows to fit a straight line, a plane, an arc, a kinked line, and a double kinked line to the helical axis. Good fits are indicated by low values of sigma2. An arc is fitted if there are at least 7 bp. A kinked line requires at least 8 bp, and the double kinked line requires at least 13 bp. The geometrical parameters are given for all models fitted, but they characterize the shape of the helical axis only if the fit is good. See Help for further explanations.

 Model      sigma2 / Å2   Geometrical parameters 
 Plane  0.020  
 Straight line (x-axis) 0.171  
 Arc  0.145 Radius of curvature:  r = 145 Å
 Kinked line  0.088 Kink angle:  alpha = 13°
 Lengths of straight segments:  l1 = 7 bp,  l2 = 2 bp