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Analysis of nucleic acid double helix geometry

Title SOLUTION NMR STRUCTURE OF THE C-TERMINAL DOMAIN OF CHICKEN GATA-1 BOUND TO DNA, 34 STRUCTURES
PDB code 3GAT   (PDB summary)
NDB code 3GAT (NDB atlas)
Duplex length 16 base pairs
Protein Erythroid transcription factor GATA-1, Transcription factor, DNA binding domain: Cys4 zinc finger, divers

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 T102 T103 G104 C105 A106 G107 A108 T109 A110 A111 A112 C113 A114 T115 T116 3'
Strand 2    3' C132 A131 A130 C129 G128 T127 C126 T125 A124 T123 T122 T121 G120 T119 A118 A117 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 C132            
    3.8 -0.5 -0.3 31° -4° -0°
T102 A131            
    3.0 0.1 -0.2 31° -1°
T103 A130            
    3.8 0.8 0.4 42° -5° -1°
G104 C129            
    4.6 -0.1 -0.0 33° 11° -2°
C105 G128            
    3.4 -0.4 0.2 41° -1° -2°
A106 T127            
    3.6 0.5 -0.4 24°
G107 C126            
    3.4 -0.5 -0.1 44°
A108 T125            
    3.2 0.3 -0.6 26° -5° -8°
T109 A124            
    3.7 0.7 0.6 46° -2° -3°
A110 T123            
    4.0 -0.2 -0.1 32° -1°
A111 T122            
    3.5 0.2 0.0 41°
A112 T121            
    3.0 -0.4 -0.5 32° -4°
C113 G120            
    3.1 -0.5 0.1 41° -2° -2°
A114 T119            
    3.2 0.2 -0.5 30° -4° -1°
T115 A118            
    4.1 0.7 0.2 36° -0° -1°
T116 A117            


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 

    C3'-exo -110° G101 C132 -126° O1'-endo    
 50°   -84° (BI)             -89° (BI)   50° 
    C1'-exo -118° T102 A131 -116° C1'-exo    
 50°   -90° (BI)             -89° (BI)   50° 
    C1'-exo -120° T103 A130 -117° C1'-exo    
 51°   -88° (BI)             -82° (BI)   50° 
    C2'-endo -109° G104 C129 -115° C2'-endo    
 50°   -88° (BI)             -80° (BI)   55° 
    C1'-exo -120° C105 G128 -118° C1'-exo    
 50°   -89° (BI)             -90° (BI)   50° 
    C1'-exo -117° A106 T127 -120° C1'-exo    
 50°   -90° (BI)             -84° (BI)   50° 
    C1'-exo -120° G107 C126 -121° C4'-exo    
 50°   -80° (BI)             -80° (BI)   50° 
    C2'-endo -111° A108 T125 -110° C1'-exo    
 53°   -80° (BI)             -90° (BI)   56° 
    C1'-exo -120° T109 A124 -110° C3'-exo    
 50°   -81° (BI)             -65° (BI)   53° 
    C3'-exo -110° A110 T123 -112° C2'-endo    
 60°   -81° (BI)             -83° (BI)   50° 
    C1'-exo -120° A111 T122 -120° O1'-endo    
 51°   -91° (BI)             -89° (BI)   50° 
    C2'-endo -110° A112 T121 -120° O1'-endo    
 50°   -80° (BI)             -90° (BI)   50° 
    C2'-endo -118° C113 G120 -111° C1'-exo    
 50°   -90° (BI)             -89° (BI)   53° 
    C2'-endo -110° A114 T119 -116° C1'-exo    
 50°   -85° (BI)             -89° (BI)   52° 
    O1'-endo -120° T115 A118 -110° C2'-endo    
 52°   -83° (BI)             -86° (BI)   50° 
    O1'-endo -121° T116 A117 -110° C4'-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