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Analysis of nucleic acid double helix geometry

Title RETINOID X RECEPTOR-THYROID HORMONE RECEPTOR DNA-BINDING DOMAIN HETERODIMER BOUND TO THYROID RESPONSE ELEMENT DNA
PDB code 2NLL   (PDB summary)
NDB code PDR021 (NDB atlas)
Duplex length 18 base pairs
Protein Retinoid X receptor-thyroid hormone receptor, Transcription factor, DNA binding domain: Cys4 zinc finger, nuclear receptor type

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' C502 A503 G504 G505 T506 C507 A508 T509 T510 C512 A513 G514 G515 T516 C517 A518 G519 C521 3'

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      

C502            
    3.5 -2.7 0.7 21° -11° -11°
A503 G538            
    3.8 1.4 -1.6 33°
G504 T537            
    3.5 -0.0 -0.1 34°
G505 C536            
    3.5 0.1 -0.3 30° -1°
T506 C535            
    3.2 0.6 0.6 44° 13°
C507 A534            
    3.3 -1.3 1.0 34° -3° -2°
A508 G533            
    3.3 0.4 -0.4 36° -6°
T509 T532            
    3.5 -0.3 0.1 35°
T510 A531            
    3.4 -0.1 -0.3 36°
C512 A530            
    3.3 0.8 0.5 35°
A513 A529            
    3.5 -0.9 0.1 36° -5°
G514 G528            
    3.2 0.5 -0.1 33° 12°
G515 T527            
    3.5 -0.1 -0.6 35° -1°
T516 C526            
    3.4 -0.1 -1.0 28° -1°
C517 C525            
    3.1 1.1 1.1 37° -1° 12°
A518 A524            
    3.5 -0.9 0.7 39° -5° -5°
G519 G523            
    3.7 0.3 -0.6 37° -3°
C521 T522            


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 -100° C502 -81° C2'-endo    
 152°   129° (BII)             -82° (BI)   60° 
    C2'-endo -137° A503 G538 -101° C1'-exo    
 173°   -4° (BI)             -120° (BI)   150° 
    O1'-endo -136° G504 T537 -157° C1'-exo    
 85°   -99° (BI)             -50° (BI)   27° 
    C4'-exo -156° G505 C536 -123° O1'-endo    
 -178°   -51° (BI)             -22° (BI)   68° 
    C1'-exo -165° T506 C535 -128° C2'-endo    
 6°   -12° (BI)             38° (BII)   53° 
    C1'-exo -88° C507 A534 -89° C2'-endo    
 109°   -134° (BI)             -72° (BI)   60° 
    C2'-endo -96° A508 G533 -124° C1'-exo    
 27°   -99° (BI)             -83° (BI)   48° 
    C1'-exo -112° T509 T532 -122° C1'-exo    
 76°   -119° (BI)             -51° (BI)   38° 
    C1'-exo -111° T510 A531 -100° C1'-exo    
 49°   -73° (BI)             -67° (BI)   43° 
    C1'-exo -115° C512 A530 -110° C2'-endo    
 71°   -92° (BI)             27° (BII)   38° 
    C1'-exo -103° A513 A529 -89° C2'-endo    
 176°   71° (BII)             -58° (BI)   88° 
    C3'-endo -172° G514 G528 -111° C1'-exo    
 56°   -92° (BI)             -116° (BI)   64° 
    C2'-endo -112° G515 T527 -127° O1'-endo    
 48°   -87° (BI)             -124° (BI)   35° 
    C2'-endo -121° T516 C526 -107° O1'-endo    
 48°   -74° (BI)             -74° (BI)   47° 
    C1'-exo -121° C517 C525 -77° C2'-endo    
 39°   -70° (BI)             81° (BII)   49° 
    C2'-endo -70° A518 A524 -88° C2'-endo    
 27°   89° (BII)             -81° (BI)   52° 
    C3'-exo -87° G519 G523 -120° C1'-exo    
 54°   -143° (BI)             -98° (BI)   29° 
    C2'-endo -85° C521 T522 -106° 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