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Analysis of nucleic acid double helix geometry

Title ENGRAILED HOMEODOMAIN Q50A VARIANT DNA COMPLEX
PDB code 1DU0   (PDB summary)
NDB code PD0114 (NDB atlas)
Duplex length 20 base pairs
Protein Engrailed, Transcription factor, DNA binding domain: Helix-turn-helix, homeodomain

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' T202 T203 T204 G205 C206 C207 A208 T209 G210 T211 A212 A213 T214 T215 A216 C217 C218 T219 A220 A221 3'
Strand 2    3' A321 A320 A319 C318 G317 G316 T315 A314 C313 A312 T311 T310 A309 A308 T307 G306 G305 A304 T303 T302 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      

T202 A321            
    3.6 1.0 0.3 39° -3°
T203 A320            
    3.0 -1.2 -0.1 33° -2°
T204 A319            
    3.6 0.4 -0.1 30°
G205 C318            
    3.1 -0.1 0.0 31° -1°
C206 G317            
    3.3 -0.4 0.0 34° -1°
C207 G316            
    3.5 0.3 0.5 42° -5°
A208 T315            
    3.2 -0.4 -0.3 35° -0° -1°
T209 A314            
    3.5 0.3 0.0 40° -4° -1°
G210 C313            
    3.1 -0.1 -0.4 24°
T211 A312            
    3.4 -0.8 1.0 42° -2° -1°
A212 T311            
    3.4 0.3 -0.3 36° -1° -2°
A213 T310            
    3.2 -0.5 -0.6 32° -3° -1°
T214 A309            
    3.2 -0.1 0.2 35° -1°
T215 A308            
    3.1 -0.1 -0.2 30° -4°
A216 T307            
    3.0 0.6 -0.3 26°
C217 G306            
    3.6 -0.7 -0.3 41° -1°
C218 G305            
    3.0 0.1 0.3 33°
T219 A304            
    3.2 0.1 -0.5 28°
A220 T303            
    3.2 0.1 0.1 36° -1°
A221 T302            


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 -117° T202 A321 -106° C2'-endo    
 42°   -91° (BI)             39° (BII)   44° 
    C2'-endo -93° T203 A320 -100° C2'-endo    
 43°   39° (BII)             -64° (BI)   37° 
    C2'-endo -110° T204 A319 -123° C1'-exo    
 20°   -17° (BI)             37° (BII)   46° 
    C2'-endo -92° G205 C318 -98° C2'-endo    
 17°   112° (BII)             -89° (BI)   -69° 
    C2'-endo -95° C206 G317 -111° C3'-exo    
 45°   13° (BI)             -61° (BI)   38° 
    C2'-endo -107° C207 G316 -102° C2'-endo    
 38°   25° (BII)             43° (BII)   40° 
    C2'-endo -107° A208 T315 -92° C2'-endo    
 43°   -34° (BI)             -84° (BI)   38° 
    C2'-endo -108° T209 A314 -108° C2'-endo    
 44°   -58° (BI)             93° (BII)   31° 
    C2'-endo -109° G210 C313 -90° C2'-endo    
 40°   -75° (BI)             -56° (BI)   41° 
    C2'-endo -95° T211 A312 -84° C2'-endo    
 48°   48° (BII)             -88° (BI)   43° 
    C2'-endo -108° A212 T311 -110° C2'-endo    
 40°   -80° (BI)             -62° (BI)   38° 
    C2'-endo -117° A213 T310 -115° C1'-exo    
 39°   -82° (BI)             -78° (BI)   35° 
    C2'-endo -109° T214 A309 -112° C1'-exo    
 42°   -86° (BI)             -30° (BI)   38° 
    C2'-endo -106° T215 A308 -107° C1'-exo    
 41°   -68° (BI)             -71° (BI)   57° 
    C1'-exo -106° A216 T307 -130° C2'-endo    
 36°   -47° (BI)             -77° (BI)   42° 
    C1'-exo -99° C217 G306 -148° O1'-endo    
 11°   26° (BII)             -64° (BI)   35° 
    C1'-exo -135° C218 G305 -104° C2'-endo    
 61°   -73° (BI)             -3° (BI)   44° 
    C2'-endo -122° T219 A304 -103° C2'-endo    
 40°   -83° (BI)             -83° (BI)   43° 
    C2'-endo -103° A220 T303 -103° C2'-endo    
 46°   -24° (BI)             -77° (BI)   49° 
    C2'-endo -109° A221 T302 -121° 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