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Analysis of nucleic acid double helix geometry

Title CRYSTAL STRUCTURE OF TETRACYCLINE REPRESSOR/OPERATOR COMPLEX
PDB code 1QPI   (PDB summary)
NDB code PD0122 (NDB atlas)
Duplex length 15 base pairs
Protein Tetracycline repressor, Transcription factor

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' C1 C2 T3 A4 T5 C6 A7 A8 T9 G10 A11 T12 A13 G14 A15 3'
Strand 2    3' G15 G14 A13 T12 A11 G10 T9 T8 A7 C6 T5 A4 T3 C2 T1 5'

Warning
  15 base(s) in syn conformation detected.
  Helix parameters and curvilinear axis from CURVES are meaningless (see Help).


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.


Backbone parameters

Table 1.  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 

    -Pucker -103° C1 G15 -Pucker    
 0°   143° (BII)             140° (BII)   0° 
    -Pucker -130° C2 G14 -Pucker    
 0°   96° (BII)             121° (BII)   0° 
    -Pucker -107° T3 A13 -Pucker    
 0°   67° (BII)             131° (BII)   0° 
    -Pucker -142° A4 T12 -Pucker    
 0°   96° (BII)             141° (BII)   0° 
    -Pucker -89° T5 A11 -Pucker    
 0°   111° (BII)             92° (BII)   0° 
    -Pucker -113° C6 G10 -Pucker    
 0°   84° (BII)             156° (BII)   0° 
    -Pucker -95° A7 T9 -Pucker    
 0°   95° (BII)             103° (BII)   0° 
    -Pucker -103° A8 T8 -Pucker    
 0°   103° (BII)             95° (BII)   0° 
    -Pucker -91° T9 A7 -Pucker    
 0°   156° (BII)             84° (BII)   0° 
    -Pucker -110° G10 C6 -Pucker    
 0°   92° (BII)             111° (BII)   0° 
    -Pucker -114° A11 T5 -Pucker    
 0°   141° (BII)             96° (BII)   0° 
    -Pucker -113° T12 A4 -Pucker    
 0°   131° (BII)             67° (BII)   0° 
    -Pucker -114° A13 T3 -Pucker    
 0°   121° (BII)             96° (BII)   0° 
    -Pucker -71° G14 C2 -Pucker    
 0°   140° (BII)             143° (BII)   0° 
    -Pucker -120° A15 T1 -Pucker    


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