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Analysis of nucleic acid double helix geometry

Title CRYSTAL STRUCTURE OF A HUMAN TBP CORE DOMAIN-HUMAN TFIIB CORE DOMAIN COMPLEX BOUND TO AN EXTENDED, MODIFIED ADENOVIRAL MAJOR LATE PROMOTER (ADMLP)
PDB code 1C9B   (PDB summary)
NDB code PD0112 (NDB atlas)
Duplex length 17 base pairs
Protein TBP/TFIIB, Transcription factor, DNA binding domain: TATA box binding protein

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' G2 G3 C4 G5 C6 C7 T8 A9 T10 A11 A12 A13 A14 G15 G16 G17 G18 3'
Strand 2    3' C118 C117 G116 C115 G114 G113 A112 T111 A110 T109 T108 T107 T106 C105 C104 C103 C102 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      

G2 C118            
    3.1 0.4 0.1 34°
G3 C117            
    3.3 -1.2 0.0 30° -9° -0°
C4 G116            
    3.6 1.0 0.9 38° -9°
G5 C115            
    3.1 -0.6 -0.2 31° -5° -2°
C6 G114            
    3.6 -0.6 -0.3 36° -11° -6°
C7 G113            
    3.4 0.9 0.6 37° -12°
T8 A112            
    3.4 -0.2 -1.4 31° 35°
A9 T111            
    2.4 -1.0 -1.3 22° 14°
T10 A110            
    3.6 -0.1 1.5 29° -12°
A11 T109            
    2.6 0.3 0.0 22° 13°
A12 T108            
    3.2 -0.3 0.4 32° -0°
A13 T107            
    2.9 0.5 0.2 31° -0°
A14 T106            
    3.5 -0.6 -0.6 29° 28° -2°
G15 C105            
    3.0 0.0 -0.1 32° -9°
G16 C104            
    3.2 -0.4 -0.1 31° -8°
G17 C103            
    3.1 0.1 -0.5 28° -5° -4°
G18 C102            


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 -114° G2 C118 -112° C2'-endo    
 48°   -79° (BI)             -35° (BI)   32° 
    C2'-endo -103° G3 C117 -99° C2'-endo    
 44°   18° (BI)             -69° (BI)   47° 
    C2'-endo -118° C4 G116 -114° C2'-endo    
 46°   -68° (BI)             53° (BII)   47° 
    C2'-endo -91° G5 C115 -98° C2'-endo    
 48°   -24° (BI)             -60° (BI)   49° 
    C1'-exo -113° C6 G114 -116° C2'-endo    
 39°   -62° (BI)             -85° (BI)   50° 
    O1'-endo -141° C7 G113 -118° C2'-endo    
 38°   -84° (BI)             40° (BII)   37° 
    C4'-exo -136° T8 A112 -93° C2'-endo    
 33°   -76° (BI)             -61° (BI)   38° 
    C2'-endo -124° A9 T111 -95° C1'-exo    
 -61°   -42° (BI)             -80° (BI)   51° 
    C1'-exo -109° T10 A110 -103° C4'-exo    
 36°   -67° (BI)             -53° (BI)   -53° 
    C1'-exo -89° A11 T109 -79° C1'-exo    
 -7°   -52° (BI)             -41° (BI)   29° 
    C1'-exo -73° A12 T108 -91° C1'-exo    
 39°   -58° (BI)             -74° (BI)   -31° 
    O1'-endo -97° A13 T107 -90° C2'-endo    
 33°   -74° (BI)             -38° (BI)   24° 
    C1'-exo -96° A14 T106 -99° C2'-endo    
 44°   -48° (BI)             -55° (BI)   15° 
    C2'-endo -82° G15 C105 -126° C1'-exo    
 -95°   -24° (BI)             -71° (BI)   41° 
    C3'-exo -133° G16 C104 -129° C1'-exo    
 44°   -99° (BI)             -98° (BI)   39° 
    C2'-endo -112° G17 C103 -125° C2'-endo    
 51°   -58° (BI)             -95° (BI)   39° 
    C1'-exo -137° G18 C102 -139° C1'-exo    


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