Re: Phi and Psi angles

Catherine O'Malley (
Thu, 6 Jun 1996 20:20:35 -0600

On Jun 6, 6:53pm, Catherine O'Malley wrote:
> I read a BioMoo transcript in which it was stated (by John Walshaw, I
> believe) that alpha helices and beta strands could be determined by phi
> and psi angles. Can anyone tell me if these angles can be determined
> using Rasmol?
>-- End of excerpt from Catherine O'Malley

Dear Cathy,

refer to the RasMol Homepage at:

Under the link to the RasMol 2.6 beta2 version there are two documents, called
26beta1.txt and 26beta2.txt (the former also available as postscript and
MS-Word-Document), in which the new features of Rasmol are explained (It's
always nice to read the manuals... ;-).

I just copied the torsional angle section from there:

[3.2] Measuring Distances, Angles and Torsions.
In addition to enabling and disabling picking, RasMol version 2.6
allows the interactive measurement of distances, angles and torsions.
This functionality is achieved using the commands "set picking
distance", "set picking angle" and "set picking torsion" respectively.
In these modes, clicking on an atom results in it being identified
on the rasmol command line. In addition every atom picked increments
a modulo counter such that in distance mode, every second atom
displays the distance between this atom and the previous one.
In angle mode, every third atom displays the angle between the
previous three atoms and in torsion mode every fourth atom displays
the torsion between the last four atoms. By holding down the shift
key while picking an atom, this modulo counter is not incremented
and allows, for example, the distances of consecutive atoms from a
fixed atom to be displayed.

I hope, this is the answer to your question - at least it's the only one I
have... ;-)

Many greetings!


     / Horst Joachim Schirra    Phone: (+49)89/8578-2826             /
    / NMR-Arbeitsgruppe        Fax:   (+49)89/8578-3777             / 
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