[gmx-users] lateral and radial tilts question

[Berk Hess]

>From: Serge Yefimov <s.yefimov at rug.nl>
>Reply-To: Discussion list for GROMACS users <gmx-users at gromacs.org>
>To: gmx-users at gromacs.org
>Subject: [gmx-users] lateral and radial tilts question
>Date: Thu, 12 Jan 2006 10:04:09 +0100
>
>Dear All,
>
>I use g_bundle to analyze the orientations and other properties of helix
>bundles in the transmembrane part of a homopentamer (MscL). Among other
>useful things g_bundle calculates three possible tilt angles and I have
>trouble with identifying the lateral and radial tilts. I would
>appreciate if someone can explain me how to identify those two angles.
>Thanx a lot for possible replies.

If you define a plane parallel to the z-axis and going through
the center of the bundle and center of the helix,
then I have defined the radial angle as the angle of the projection
of the helix axis on the plane with the z-axis
and the lateral angle the angle of the helix with this plane.

Berk.