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Analysis of nucleic acid double helix geometry

Title SOLUTION NMR STRUCTURE OF THE GAGA FACTOR/DNA COMPLEX, 50 STRUCTURES
PDB code 1YUJ   (PDB summary)
NDB code 1YUJ (NDB atlas)
Duplex length 11 base pairs
Protein GAGA binding factor, DNA packing/chromatin, DNA binding domain: Cys2-His2 zinc finger

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' G101 C102 C103 G104 A105 G106 A107 G108 T109 A110 C111 3'
Strand 2    3' C122 G121 G120 C119 T118 C117 T116 C115 A114 T113 G112 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      

G101 C122            
    4.3 -0.2 0.2 35° -9°
C102 G121            
    2.9 0.4 -0.3 35° -2°
C103 G120            
    4.3 -0.1 0.3 35° -3°
G104 C119            
    3.1 0.4 -0.1 30°
A105 T118            
    4.2 -0.5 -0.2 36° -1° -4°
G106 C117            
    3.9 0.5 0.3 36° -6°
A107 T116            
    5.0 -0.4 0.2 38° 18°
G108 C115            
    3.2 0.5 -0.8 32° -3° -6°
T109 A114            
    2.8 -0.4 0.3 36° -8° -4°
A110 T113            
    4.4 0.5 -0.1 30° -2° -3°
C111 G112            


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 -136° G101 C122 -122° O1'-endo    
 70°   -81° (BI)             -95° (BI)   47° 
    O1'-endo -129° C102 G121 -123° O1'-endo    
 51°   -109° (BI)             -106° (BI)   70° 
    O1'-endo -116° C103 G120 -130° C1'-exo    
 54°   -101° (BI)             -96° (BI)   47° 
    C1'-exo -117° G104 C119 -119° O1'-endo    
 75°   -101° (BI)             -95° (BI)   37° 
    C1'-exo -125° A105 T118 -123° O1'-endo    
 70°   -85° (BI)             -91° (BI)   90° 
    C1'-endo -124° G106 C117 -120° C1'-exo    
 74°   -109° (BI)             -24° (BI)   72° 
    O1'-endo -122° A107 T116 -122° O1'-endo    
 77°   -95° (BI)             -113° (BI)   20° 
    C2'-endo -122° G108 C115 -113° C3'-endo    
 39°   -97° (BI)             -87° (BI)   58° 
    O1'-endo -129° T109 A114 -112° C1'-exo    
 48°   -104° (BI)             -89° (BI)   58° 
    C3'-endo -114° A110 T113 -123° O1'-endo    
 68°   -111° (BI)             -84° (BI)   30° 
    C1'-exo -129° C111 G112 -122° 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