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Analysis of nucleic acid double helix geometry

Title HIV-1 REVERSE TRANSCRIPTASE CROSSLINKED TO POST- TRANSLOCATION AZTMP-TERMINATED DNA (COMPLEX P)
PDB code 1N5Y   (PDB summary)
NDB code PD0365 (NDB atlas)
Duplex length 20 base pairs
Protein POL polyprotein [Contains: Protease (Retropepsin) (EC 3.4.23.16); Reverse transcriptase (EC 2.7.7.49); Ribonuclease H (EC 3.1.26.4)], Virus

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' A706 G707 G708 C709 G710 C711 C712 C713 G714 A715 A716 C717 A718 G719 G720 G721 A722 C723 T724 G725 3'

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      

A706            
    2.6 -0.2 -0.0 32° 11° -0°
G707            
    3.2 -0.2 -0.7 30°
G708 C821            
    2.4 -0.2 -0.5 25° -3°
C709 C820            
    4.0 0.7 -0.3 35° -2°
G710 G819            
    2.5 -0.1 -0.4 30°
C711 C818            
    3.5 0.4 0.6 42° -3°
C712 G816            
    2.7 0.4 -0.3 33° -1°
C713 G815            
    3.6 0.6 0.6 33° -5°
G714 C814            
    3.5 -0.8 0.1 39° -1°
A715 T813            
    3.1 -0.3 0.0 34° -1°
A716 T812            
    2.9 0.7 -1.0 28° -7° -12°
C717 G811            
    3.6 0.3 0.3 41° -0° 10°
A718 T810            
    3.0 0.0 0.3 29° -3°
G719 C809            
    3.1 -0.3 0.2 32° -0°
G720 C808            
    2.9 0.3 -0.1 35° -5°
G721 C807            
    3.9 0.1 0.1 36° -6°
A722 T806            
    3.3 0.2 -1.1 30° -12°
C723 G805            
    2.8 0.2 0.1 33° 18°
T724 A804            
    3.9 -0.1 0.9 49° -3° -10°
G725 C803            


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 

    C3'-endo -149° A706 -131° C2'-exo    
 44°   -82° (BI)             -116° (BI)   35° 
    C3'-endo -150° G707 -131° C3'-endo    
 32°   -105° (BI)             -117° (BI)   53° 
    C3'-endo -146° G708 C821 -119° C3'-endo    
 47°   -95° (BI)             -157° (BI)   51° 
    C3'-endo -136° C709 C820 -138° C3'-endo    
 54°   -142° (BI)             -170° (BII)   47° 
    C3'-endo -156° G710 G819 -129° C3'-endo    
 68°   -99° (BI)             -144° (BI)   80° 
    C3'-endo -137° C711 C818 -117° C2'-exo    
 57°   -123° (BI)             -106° (BI)   64° 
    C3'-endo -132° C712 G816 -120° C3'-endo    
 13°   -82° (BI)             -83° (BI)   37° 
    C3'-endo -128° C713 G815 -114° C3'-endo    
 62°   -132° (BI)             2° (BI)   42° 
    C2'-endo -107° G714 C814 -100° C2'-endo    
 59°   -90° (BI)             -102° (BI)   37° 
    C2'-endo -115° A715 T813 -95° C2'-endo    
 33°   -22° (BI)             -88° (BI)   40° 
    C2'-endo -112° A716 T812 -90° C2'-endo    
 27°   -112° (BI)             -82° (BI)   35° 
    C2'-endo -119° C717 G811 -112° C2'-endo    
 41°   -110° (BI)             -55° (BI)   40° 
    C3'-exo -92° A718 T810 -94° C2'-endo    
 48°   -82° (BI)             -26° (BI)   35° 
    C2'-endo -89° G719 C809 -91° C2'-endo    
 39°   -29° (BI)             -124° (BI)   -54° 
    C3'-exo -90° G720 C808 -92° C3'-exo    
 4°   -35° (BI)             -49° (BI)   64° 
    C2'-endo -87° G721 C807 -116° C2'-endo    
 43°   -98° (BI)             -72° (BI)   -46° 
    C2'-endo -90° A722 T806 -100° C2'-endo    
 37°   -53° (BI)             -45° (BI)   61° 
    C1'-exo -139° C723 G805 -102° C2'-endo    
 49°   -99° (BI)             -101° (BI)   54° 
    C2'-endo -86° T724 A804 -80° C3'-exo    
 53°   -6° (BI)             -89° (BI)   -163° 
    C1'-exo -126° G725 C803 -129° 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