g_bundle (1) Linux Manual Page

g_bundle – analyzes bundles of axes, e.g. helices

VERSION 4.0.1

Synopsis

g_bundle -f traj.xtc -s topol.tpr -n index.ndx -ol bun_len.xvg -od bun_dist.xvg -oz bun_z.xvg -ot bun_tilt.xvg -otr bun_tiltr.xvg -otl bun_tiltl.xvg -ok bun_kink.xvg -okr bun_kinkr.xvg -okl bun_kinkl.xvg -oa axes.pdb -[no]h -nice int -b time -e time -dt time -tu enum -[no]xvgr -na int -[no]z

Description

g_bundle analyzes bundles of axes. The axes can be for instance helix axes. The program reads two index groups and divides both of them in -na parts. The centers of mass of these parts define the tops and bottoms of the axes. Several quantities are written to file: the axis length, the distance and the z-shift of the axis mid-points with respect to the average center of all axes, the total tilt, the radial tilt and the lateral tilt with respect to the average axis.

With options -ok, -okr and -okl the total, radial and lateral kinks of the axes are plotted. An extra index group of kink atoms is required, which is also divided into -na parts. The kink angle is defined as the angle between the kink-top and the bottom-kink vectors.

With option -oa the top, mid (or kink when -ok is set) and bottom points of each axis are written to a pdb file each frame. The residue numbers correspond to the axis numbers. When viewing this file with rasmol, use the command line option -nmrpdb, and type set axis true to display the reference axis.

Files

-f traj.xtc Input
 Trajectory: xtc trr trj gro g96 pdb cpt 

-s topol.tpr Input
 Structure+mass(db): tpr tpb tpa gro g96 pdb 

-n index.ndx Input, Opt.
 Index file 

-ol bun_len.xvg Output
 xvgr/xmgr file 

-od bun_dist.xvg Output
 xvgr/xmgr file 

-oz bun_z.xvg Output
 xvgr/xmgr file 

-ot bun_tilt.xvg Output
 xvgr/xmgr file 

-otr bun_tiltr.xvg Output
 xvgr/xmgr file 

-otl bun_tiltl.xvg Output
 xvgr/xmgr file 

-ok bun_kink.xvg Output, Opt.
 xvgr/xmgr file 

-okr bun_kinkr.xvg Output, Opt.
 xvgr/xmgr file 

-okl bun_kinkl.xvg Output, Opt.
 xvgr/xmgr file 

-oa axes.pdb Output, Opt.
 Protein data bank file 

Other Options

-[no]hno
 Print help info and quit

-nice int 19
 Set the nicelevel

-b time 0
 First frame (ps) to read from trajectory

-e time 0
 Last frame (ps) to read from trajectory

-dt time 0
 Only use frame when t MOD dt = first time (ps)

-tu enum ps
 Time unit:  ps,  fs,  ns,  us,  ms or  s

-[no]xvgryes
 Add specific codes (legends etc.) in the output xvg files for the xmgrace program

-na int 0
 Number of axes

-[no]zno
 Use the Z-axis as reference iso the average axis

See Also

gromacs(7)

More information about GROMACS is available at <http://www.gromacs.org/>.