The asymmetric unit is composed of two monomers of 90 residues. Two molecules of LMPC are bound per monomer. The wheat ns-LTP1 consists of four helices, H1 (residues 3–17), H2 (residues 25–37), H3 (residues 41–55), and H4 (residues 63–73) and a long C-terminal loop LCter (residues 74–90) ( Fig. 1). The helices were defined using the program DSSP . They are linked by three loops, L1-2 (residues 18–24), L2-3 (residues 38–40) and L3-4 (residues 56–62). Helix H1 is significantly bent around Pro13 and helix H4, at Ile69, before the doublet Pro70-Pro71. LCter is a long winding loop made of two successive turns (residues 74–80 and residues 81–90) maintained close to the core of the structure by the disulphide bridge Cys48-Cys87. The structure contains two pairs of disulphide bridges located by pairs at opposite sides of the protein ( Fig. 1). Electron density maps reveal clear unique conformations for the disulphide bridges Cys13-Cys27, Cys28-Cys73 and Cys48-Cys87, while two alternate conformations are observed for the Cys3-Cys50 disulphide bond. In all loops, the electron density is well defined and atomic B-factors for the main chain atoms are below 30 Å2. The protein is best described as a helix bundle with H1/H2 and H3/H4 (including LCter) forming two antiparallel helix sets, surrounding a strikingly large tunnel which runs through the protein ( Fig. 2) covered predominantly with hydrophobic residues: Val10 and Cys13 from helix H1, Cys27, Val31 and Leu34 from helix H2, Ala38 from loop L2–3, Ala47, Cys48, Leu51, Lys52 and Ala55 from helix H3, Leu61 from loop L3–4, Ala66, Arg67, Ile69 and Pro70 from helix H4 and Val75, Leu77, Tyr79, Ile81, Ser82, Leu83 and Ile85 from loop LCter. The two extremities of the tunnel are exposed to the solvent and include both hydrophobic or hydrophilic residues: Asp7, Arg11, Leu14, Ile54 and Ile58 on one side, and His35, Arg44, Pro78 and Val90 on the other side. The two monomers of the asymmetric unit, which were refined independently, have similar conformations with root mean square (rms) deviations of 0.32 Å for the main chain atoms and 0.9 Å for all atoms.