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Analysis of nucleic acid double helix geometry

Title CRYSTAL STRUCTURE OF THE DNA-BINDING DOMAIN OF INTRON ENDONUCLEASE I-TEVI WITH ITS SUBSTRATE
PDB code 1I3J   (PDB summary)
NDB code PD0200 (NDB atlas)
Duplex length 20 base pairs
Protein INTRON ENDONUCLEASE I-TEVI, Nuclease, DNA binding domain: Zinc finger|alpha-helix, DNA binding domain: Helix-turn-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' T2 C3 T4 T5 G6 G7 G8 T9 C10 T11 A12 C13 C14 G15 T16 T17 T18 A19 A20 T21 3'
Strand 2    3' A51 G50 A49 A48 C47 C46 C45 A44 G43 A42 T41 G40 G39 C38 A37 A36 A35 T34 T33 A32 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 A51            
    3.1 -0.2 -0.1 35° -1°
C3 G50            
    3.8 0.6 -0.2 40°
T4 A49            
    3.1 -0.1 -0.0 34° -2°
T5 A48            
    3.3 0.1 1.0 29° -0° -3°
G6 C47            
    3.3 -0.3 0.6 34° -1°
G7 C46            
    3.7 -0.3 -0.2 36° -5°
G8 C45            
    3.1 -0.4 -0.6 35° -2° -2°
T9 A44            
    3.1 1.0 -0.4 36°
C10 G43            
    3.2 -0.8 0.0 32°
T11 A42            
    3.2 -0.3 0.9 35° -0°
A12 T41            
    2.9 1.0 -0.4 27° -2°
C13 G40            
    3.4 0.0 -0.8 34° -1°
C14 G39            
    4.0 -0.2 0.2 31° 11°
G15 C38            
    3.3 -0.5 -0.5 32° -1°
T16 A37            
    3.0 0.5 -0.0 39° -6°
T17 A36            
    3.2 -0.0 -0.1 32°
T18 A35            
    3.4 -0.6 0.9 42° -8° -1°
A19 T34            
    3.1 0.8 -0.1 29° -5°
A20 T33            
    3.1 -0.2 -0.7 34° -4°
T21 A32            


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 -106° T2 A51 -94° C3'-exo    
 31°   -69° (BI)             -49° (BI)   49° 
    C2'-endo -85° C3 G50 -107° C3'-exo    
 14°   -70° (BI)             -14° (BI)   38° 
    C3'-exo -99° T4 A49 -86° C2'-endo    
 -59°   -46° (BI)             -45° (BI)   48° 
    C3'-exo -96° T5 A48 -83° C2'-endo    
 35°   -65° (BI)             -12° (BI)   31° 
    C2'-endo -66° G6 C47 -87° C2'-endo    
 49°   56° (BII)             -59° (BI)   17° 
    C2'-endo -90° G7 C46 -106° C2'-endo    
 57°   2° (BI)             -78° (BI)   -57° 
    C2'-endo -122° G8 C45 -112° C3'-exo    
 25°   -82° (BI)             -51° (BI)   24° 
    C2'-endo -96° T9 A44 -112° C2'-endo    
 -171°   -117° (BI)             -17° (BI)   29° 
    C2'-endo -130° C10 G43 -85° C2'-endo    
 30°   -42° (BI)             -76° (BI)   46° 
    C2'-endo -105° T11 A42 -97° C3'-exo    
 41°   -61° (BI)             -48° (BI)   36° 
    C2'-endo -93° A12 T41 -99° C2'-endo    
 -55°   -53° (BI)             -94° (BI)   -53° 
    C3'-exo -92° C13 G40 -125° C2'-endo    
 -62°   -62° (BI)             -52° (BI)   33° 
    C3'-exo -124° C14 G39 -95° C2'-endo    
 38°   -67° (BI)             -85° (BI)   -58° 
    C3'-exo -99° G15 C38 -101° C3'-exo    
 39°   -81° (BI)             -60° (BI)   32° 
    C2'-endo -103° T16 A37 -96° C2'-endo    
 -53°   -48° (BI)             -58° (BI)   24° 
    C3'-exo -107° T17 A36 -85° C2'-endo    
 30°   -91° (BI)             -82° (BI)   42° 
    C2'-endo -84° T18 A35 -85° C3'-exo    
 48°   -13° (BI)             -57° (BI)   26° 
    C2'-endo -93° A19 T34 -93° C2'-endo    
 25°   -92° (BI)             -56° (BI)   -80° 
    C2'-endo -87° A20 T33 -109° C2'-endo    
 -76°   -50° (BI)             4° (BI)   47° 
    C3'-exo -120° T21 A32 -85° 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