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Analysis of nucleic acid double helix geometry

Title GLUCOCORTICOID RECEPTOR MUTANT/DNA COMPLEX
PDB code 1LAT   (PDB summary)
NDB code PDT030 (NDB atlas)
Duplex length 18 base pairs
Protein Glucocorticoid 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' T2 C3 C4 A5 G6 A7 A8 C9 A10 T11 G12 T13 T14 C15 T16 G17 G18 A19 3'
Strand 2    3' A19 G18 G17 T16 C15 T14 T13 G12 T11 A10 C9 A8 A7 G6 A5 C4 C3 T2 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      

T2 A19            
    3.3 0.1 -0.8 34° -2°
C3 G18            
    3.4 -0.4 -0.1 26°
C4 G17            
    3.3 0.1 1.2 49° -13°
A5 T16            
    3.2 0.0 -0.2 27° -5°
G6 C15            
    3.1 -0.7 -0.1 36° -7°
A7 T14            
    3.3 0.2 0.1 37° -5° -5°
A8 T13            
    3.5 0.0 -0.4 34° -3°
C9 G12            
    3.8 0.3 -0.1 33° 13° -7°
A10 T11            
    3.9 -0.1 -0.4 29°
T11 A10            
    3.8 -0.3 -0.1 31° 12°
G12 C9            
    3.7 0.0 -0.3 35°
T13 A8            
    3.1 -0.2 -0.1 35° -2°
T14 A7            
    3.1 0.6 -0.0 39° -0°
C15 G6            
    3.2 0.4 -0.2 24°
T16 A5            
    3.6 -0.6 1.2 47° -17°
G17 C4            
    3.3 0.3 0.0 31° -5°
G18 C3            
    3.4 0.2 -0.9 31° -4° -4°
A19 T2            


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 

    C1'-exo -126° T2 A19 -154° C2'-endo    
 60°   -78° (BI)             -76° (BI)   61° 
    C4'-exo -145° C3 G18 -102° C1'-exo    
 58°   -76° (BI)             -83° (BI)   60° 
    C2'-endo -100° C4 G17 -91° C3'-exo    
 39°   23° (BII)             108° (BII)   25° 
    C3'-exo -80° A5 T16 -83° C2'-endo    
 56°   -70° (BI)             -64° (BI)   39° 
    C1'-exo -93° G6 C15 -99° C1'-exo    
 41°   -6° (BI)             -84° (BI)   77° 
    C2'-endo -104° A7 T14 -124° C1'-exo    
 58°   -49° (BI)             -80° (BI)   51° 
    C1'-exo -109° A8 T13 -109° C2'-endo    
 69°   -90° (BI)             -87° (BI)   57° 
    O1'-endo -123° C9 G12 -124° C1'-exo    
 56°   -95° (BI)             -85° (BI)   61° 
    O1'-endo -130° A10 T11 -144° O1'-endo    
 56°   -87° (BI)             -94° (BI)   62° 
    O1'-endo -139° T11 A10 -132° O1'-endo    
 54°   -82° (BI)             -95° (BI)   63° 
    C1'-exo -121° G12 C9 -121° C1'-exo    
 62°   -80° (BI)             -108° (BI)   67° 
    C1'-exo -118° T13 A8 -102° C1'-exo    
 62°   -79° (BI)             -87° (BI)   39° 
    C1'-exo -124° T14 A7 -107° C2'-endo    
 52°   -94° (BI)             16° (BI)   64° 
    C1'-exo -108° C15 G6 -99° C1'-exo    
 42°   -76° (BI)             -105° (BI)   41° 
    C2'-endo -93° T16 A5 -93° C3'-exo    
 43°   108° (BII)             -15° (BI)   84° 
    C2'-endo -88° G17 C4 -110° C1'-exo    
 56°   -89° (BI)             -95° (BI)   49° 
    C2'-endo -83° G18 C3 -142° C4'-exo    
 167°   -62° (BI)             -46° (BI)   70° 
    C1'-exo -167° A19 T2 -132° O1'-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