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Analysis of nucleic acid double helix geometry

Title STRUCTURAL BASIS OF DNA RECOGNITION BY THE HETERODIMERIC CELL CYCLE TRANSCRIPTION FACTOR E2F-DP
PDB code 1CF7   (PDB summary)
NDB code PD0045 (NDB atlas)
Duplex length 15 base pairs
Protein E2F-4/DP-2 heterodimer, Transcription factor, DNA binding domain: Helix-turn-helix, winged helix

Only the nucleic acid double helix part of the structure is analysed here. Small ligands, proteins, and overhanging ends are not taken into account. Information on the complete structure is available at the Image Library Entry page and at the Sequence, Chains, Units page.

Strand 1    5' T501 T502 T503 T504 C505 G506 C507 G508 C509 G510 G511 T512 T513 T514 T515 3'
Strand 2    3' A615 A614 A613 A612 G611 C610 G609 C608 G607 C606 C605 A604 A603 A602 A601 5'

Side view 1 Top view
Side view 1 Top view
Side view 2 3-dimensional interactive models
(Help)
  

RASMOL, CHIME, VRML 2.0, PDB

Side view 2  

Figure 1   Three orthogonal views of the double helix (Help). Residues are colored according to the nucleotide type (Help: Color codes). The curvilinear helical axis (green) was calculated with CURVES. The double helix is oriented with respect to the principle axis of inertia of the curvilinear helical axis (see Help for further explanations). This drawing reveals immediately if there is any bending of the helical axis.


Analysis of helical axis bending


Inter base pair parameters

The six inter base pair parameters (rise, shift, slide, twist, roll, tilt) describe the translational and rotational displacement between neighbouring base pairs. See Help for further explanations.

Plot of inter base pair parameters with respect to global and local helical axes:  PDF,   GIF
(Global parameters from CURVES,  local parameters from CURVES and FREEHELIX)

Table 1.  Inter base pair parameters with respect to the global helical axis, calculated with CURVES.


  Strand 1      Strand 2        riseg          shiftg          slideg          twistg         rollg         tiltg    
    / Å / Å / Å      

T501 A615            
    3.0 -0.3 -0.2 33°
T502 A614            
    3.4 -0.1 -0.1 42° -1°
T503 A613            
    3.5 0.6 -0.1 43° -1°
T504 A612            
    3.4 1.1 -0.3 30°
C505 G611            
    3.7 -1.8 0.6 36° -5° -1°
G506 C610            
    3.4 1.3 -0.2 36° -5°
C507 G609            
    3.6 -0.0 0.4 28°
G508 C608            
    3.4 -1.5 -0.2 34° -2° -7°
C509 G607            
    3.4 1.5 0.2 37° -9°
G510 C606            
    3.5 -0.7 -0.1 34° 11° -3°
G511 C605            
    3.4 -0.4 -0.5 33° -1°
T512 A604            
    3.2 -0.1 0.0 39°
T513 A603            
    3.2 -0.2 0.0 37° -2°
T514 A602            
    3.2 0.3 -0.1 40° -1°
T515 A601            


Backbone parameters

Table 2.  Selected torsional angles and sugar pucker phase angles describing the conformation of the sugar phosphate backbone. (See Help for further explanations.)


 gamma     epsilon-zeta       pucker        chi      Strand 1     Strand 2      chi        pucker       epsilon-zeta     gamma 

    C2'-endo -131° T501 A615 -142° C2'-endo    
 55°   -74° (BI)             -82° (BI)   162° 
    C2'-endo -113° T502 A614 -133° C2'-endo    
 55°   -78° (BI)             -83° (BI)   45° 
    C2'-endo -109° T503 A613 -114° C2'-endo    
 -77°   -44° (BI)             3° (BI)   48° 
    C3'-exo -116° T504 A612 -107° C2'-endo    
 49°   -116° (BI)             71° (BII)   50° 
    C1'-exo -100° C505 G611 -86° C2'-endo    
 56°   100° (BII)             -60° (BI)   44° 
    C2'-endo -114° G506 C610 -105° C2'-endo    
 7°   -103° (BI)             76° (BII)   39° 
    C2'-endo -103° C507 G609 -85° C2'-endo    
 46°   -56° (BI)             -39° (BI)   -111° 
    C2'-endo -88° G508 C608 -114° C2'-endo    
 45°   81° (BII)             -62° (BI)   166° 
    C2'-endo -117° C509 G607 -139° C2'-endo    
 162°   -122° (BI)             145° (BII)   57° 
    C2'-endo -129° G510 C606 -107° C1'-exo    
 47°   -34° (BI)             -93° (BI)   -95° 
    C2'-endo -121° G511 C605 -127° C2'-endo    
 -66°   -37° (BI)             -76° (BI)   -66° 
    C3'-exo -115° T512 A604 -108° C3'-exo    
 -63°   -59° (BI)             -54° (BI)   60° 
    C3'-exo -101° T513 A603 -105° C2'-endo    
 -63°   -72° (BI)             -103° (BI)   45° 
    C3'-exo -100° T514 A602 -109° C2'-endo    
 -70°   -80° (BI)             -63° (BI)   60° 
    C3'-exo -104° T515 A601 -132° C2'-endo    


Groove width

Plot of minor groove width:   PDF,   GIF
Plot of major groove width:   PDF,   GIF
(See Help for further explanations.)

Further information

Full output from CURVES  (helical parameters with respect to global and local axes)

Full output from FREEHELIX  (helical parameters with respect to local axis, angles between normal vectors)

Chirality of ribose and phosphate atoms
Check the naming of phosphate and ribose substituents. Recommended for phosphate oxygens and for ribose hydrogens in NMR structures.


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Perl script:    helixparameter.pl  (15 Sep 2016)
Author:    Peter Slickers  (slickers@leibniz-fli.de),  IMB Jena,  Germany