Table III.

Database Searches with the Search Algorithms

Number of matchesin databases
Search algorithmGlutenHordeinSecalinAvenin
Algorithm 1Q4XPQ7X(YFWIL)52488-
Algorithm 1 – Q4XXPQ7X(YFWIL)33491146
Algorithm 1 – Q7Q4XPXX(YFWIL)2861426011
Algorithm 2Q4XPQ7XP(YFWIL)466033-
Algorithm 2 – Q4aXXPQ7XP(YFWIL)26219689-
Algorithm 2 – Q7Q4XPXXP(YFWIL)516833-
Short algorithmQXP(YFWIL) X ≠ Pb>5002761057
Predicted epitopeQQPFPQQPQQPFPQ6122-
  • a Algorithm 2 without the specification of a Q at position 4 predicts the known gliadin α9 epitope.

  • b A proline at p2 in this algorithm inhibits deamidation of the glutamine.

  • The search algorithms reveal many matches in the gluten, hordeins, and secalin sequences but very few in the avenin sequences. The predictive algorithm 2 (QXPQXP[YFWIL]) and the less strict variants of that algorithm have no matches in the avenin database. The novel T cells stimulatory gluten peptide (QQPFPQQPQQPFPQ) is also found in the hordeins and secalin but not in the avenins. X stands for any amino acid.