> On 16 Feb 2000, Mina wrote:
>> > Recently, I found a consensus sequence described as : psi - K - X - E.
> > Can somebody tell me which amino acids belong to "psi", what
> > classification is that or just point me to a reference.
>> one possibility is that psi stands for pseudo - i.e. it means that the
> amino acids may be a pseudo-amino acid such as pseudo-proline or
> whatever residue that is unnatural or unusual. For example, the CO
> or NH group may be replaced by CH2 group so that the peptide bond
> becomes non-hydrolysable, or the side-chains has other atoms or groups
> attached or replaced.
If it was phi instead of psi, I´d guess it stands for hydroPHobic. I´ve
seen this nomenclature someplace, but i´ve not been able to find it as a
standard (IUPAC) assignment. Hydrophobic amino acids are those with
aliphatic side chains, like e.g. leucine