The following codes should be used for the unusual
Note : Some records contain entries where
residues were not fully identified. In these cases, the
sequences contain residues marked with an x to signify this
fact. The three letter codes correspondingly use 'xx'.
Where leucine could not be distinguished from isoleucine,
records are marked Lx or Lxx.
Searching for "ampull" will return all sequences from the source mould
Useful reference: Wallace, B. A. (2000). Common structural features in Gramicidin and other ion channels. Bioessays. 22(3), 227-234.
Chugh, J. K. and Wallace, B. A. (2001). Peptaibols: Models for Ion Channels. Biochem. Soc. Trans. 29(4), 565-570.