RE: [ccp4bb]: Chirality Issue

[Ulrich Baumann <ulrich.baumann@ibc.unibe.ch>]

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That's all right besides it should read "configuration" and not
"conformation".

>>>On Fri, 11 May 2001, Bernhard Rupp wrote:

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> > Never paid attention to it before. Isn't there a chirality issue with the
> > side chain of Threonine at the Cbeta position???
> > Is it always R (rectus) or can it be S also????
> 
> The amino acid threonine contains two chiral carbons and thus can 
> exist in four possible conformations.  However, only a single 
> conformation (2S, 3R) of threonine is incorporated in proteins 
> by the cellular translation material.  The conformation at the 
> alpha carbon (carbon 2) is the same as that of the other amino 
> acids in biological proteins, and there is no explanation for 
> why this enantiomer was selected.  Further, there is no explanation 
> for the choice of conformation at the 3 carbon in threonine.  
> 
> BR
>