Complete amino acid sequence determination of the major allergen of peach (Prunus persica) Pru p 1

The major protein allergen of peach (Prunus persica), Pru p1, has recently been identified as a lipid transfer protein (LTP), The complete primary str ucture of Pru p1, obtained by direct amino acid sequence and liquid chromat ography-mass spectrometry (LC-MS) analyses with the purified protein, is de scribed here. The protein consists of 91 amino acids with a calculated mole cular mass of 9178 Da. The amino acid sequence contains eight strictly cons erved cysteines, as do all known LTPs, but secondary structure predictions failed to classify the peach 9 kDa protein as an 'all-alpha type', due to t he high frequency of amino acids (nine prolines) disrupting alpha helices, Although the sequence similarity with maize LTP is only 63%, out of the 25 amino acids forming the inner surface of the tunnel-like hydrophobic cavity in maize ns-LTP 16 are identical and 7 similar in the peach homolog, suppo rting the hypothesis of a similar function.