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Analysis of nucleic acid double helix geometry

Title CRYSTAL STRUCTURE OF MAD-MAX RECOGNIZING DNA
PDB code 1NLW   (PDB summary)
NDB code PD0387 (NDB atlas)
Duplex length 18 base pairs
Protein MAD-MAX, Transcription Factor, DNA binding domain: Alpha-helix, DNA binding domain: Basic helix-loop-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' G102 A103 G104 T105 A106 G107 C108 A109 C110 G111 T112 G113 C114 T115 A116 C117 T118 C119 3'
Strand 2    3' C319 T318 C317 A316 T315 C314 G313 T312 G311 C310 A309 C308 G307 A306 T305 G304 A303 G302 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      

G102 C319            
    3.2 -0.4 0.1 38° -6° -4°
A103 T318            
    3.6 0.4 -0.1 37°
G104 C317            
    3.0 0.4 -0.7 27°
T105 A316            
    3.5 -0.8 0.5 38° -2° -6°
A106 T315            
    3.1 0.4 -0.3 34° -3°
G107 C314            
    3.3 0.4 -0.6 32°
C108 G313            
    3.4 -0.1 0.8 38°
A109 T312            
    3.1 -0.3 -0.8 29° -1° -1°
C110 G311            
    3.6 -0.2 0.7 37°
G111 C310            
    3.3 0.6 -0.5 32° -4°
T112 A309            
    3.5 -0.2 0.4 32° -0°
G113 C308            
    3.0 -0.4 -0.5 35° -1°
C114 G307            
    3.3 0.0 0.1 30° -0°
T115 A306            
    3.3 0.0 0.3 34° -1°
A116 T305            
    3.0 -0.0 -0.5 36° -4°
C117 G304            
    3.3 0.2 -0.2 34°
T118 A303            
    3.0 -0.1 0.4 32°
C119 G302            


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 -134° G102 C319 -101° C2'-endo    
 55°   -55° (BI)             -62° (BI)   50° 
    C2'-endo -113° A103 T318 -106° C2'-endo    
 42°   -91° (BI)             -65° (BI)   177° 
    C2'-endo -103° G104 C317 -151° C2'-endo    
 174°   -124° (BI)             -100° (BI)   41° 
    C2'-endo -129° T105 A316 -96° C2'-endo    
 38°   -13° (BI)             -80° (BI)   52° 
    C2'-endo -110° A106 T315 -116° C2'-endo    
 41°   -85° (BI)             -74° (BI)   -137° 
    C2'-endo -106° G107 C314 -147° C1'-exo    
 44°   -82° (BI)             25° (BII)   50° 
    C1'-exo -119° C108 G313 -96° C2'-endo    
 47°   -51° (BI)             -38° (BI)   35° 
    C2'-endo -102° A109 T312 -110° C1'-exo    
 -79°   -51° (BI)             -81° (BI)   48° 
    C3'-exo -122° C110 G311 -103° C2'-endo    
 49°   -67° (BI)             -52° (BI)   39° 
    C2'-endo -97° G111 C310 -118° C1'-exo    
 -72°   -60° (BI)             -9° (BI)   42° 
    C2'-endo -114° T112 A309 -97° C2'-endo    
 53°   -59° (BI)             -73° (BI)   -61° 
    C2'-endo -111° G113 C308 -112° C3'-exo    
 -65°   -40° (BI)             -57° (BI)   38° 
    C3'-exo -105° C114 G307 -100° C2'-endo    
 41°   -95° (BI)             -69° (BI)   40° 
    C2'-endo -101° T115 A306 -100° C2'-endo    
 44°   -67° (BI)             -81° (BI)   38° 
    C2'-endo -102° A116 T305 -106° C2'-endo    
 -70°   -48° (BI)             -91° (BI)   44° 
    C3'-exo -115° C117 G304 -111° C2'-endo    
 49°   -89° (BI)             -77° (BI)   47° 
    C2'-endo -107° T118 A303 -102° C2'-endo    
 46°   -48° (BI)             -74° (BI)   39° 
    C2'-endo -86° C119 G302 -100° 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