Three‐Dimensional Structure in Solution of a Wheat Lipid‐Transfer Protein from Multidimensional ¹H‐NMR Data

Abstract

were used to build models of the three-dimensional structure of a non-specific wheat lipid-transfer protein (LTP) by using distance geometry, simulated annealing, energy minimization and molecular dynamics techniques. A first set of 881 distance constraints derived from NOE cross-peak intensities was used to generate 74 initial structures. One family of topological mirror images of the protein structure was eliminated by considering helical secondary-structure organization and steric requirements. Back calculations of NOE intensities led us to introduce 535 additional distance constraints. Finally, 21 structures were selected as representative of the structure of the protein. The polypeptide backbone folds into a simple and original right-handed winding. It is composed of a bundle of four helices linked by flexible loops, which is packed against a C-terminal fragment forming a non-standard saxophone-like shape. The folded protein is stabilized by hydrophobic interactions and the four disulfide bridges combined by pairs on each side of the protein. An hydrophobic cleft, formed by residues located in the second half of the protein could be a potential site for the binding of lipids.

Determination of the Secondary Structure and Conformation of Puroindolines by Infrared and Raman Spectroscopy

“…Concerning other structural elements, the 3D structures of RBI and wheat ns-LTP clearly reveal lower contents of -sheet or extended structures than those estimated from spectroscopic methods like IR or CD (Strobl et al, 1995;Gincel et al, 1994;Désormeaux et al, 1992;Alagiri & Singh, 1993). The three-dimensional structure of wheat ns-LTP does not reveal the existence of -sheets and shows only 7% -sheets in the case of RBI, while IR and CD predicted a -sheet content of 20-30% for both proteins.…”

Homology modelling and molecular dynamics aided analysis of ligand complexes demonstrates functional properties of lipid‐transfer proteins encoded by the barley low‐temperature‐inducible gene family, blt4

“…ClustalV multiple amino acid sequence alignment between the deduced sequence of the low-temperature responsive barley BLT4 proteins (White et al, 1994) and three non-specific lipid-transfer proteins (LTPs) with solved tertiary structures. NLTP_MAIZE, LTP from maize seedling (Shin et al, 1995); NLT1_HORVU, barley endosperm LTP (Heinemann et al, 1996); NLTA_WHEAT, LTP isolated from wheat seeds (Gincel et al, 1994). Sequence codes correspond to Swiss-Prot access codes.…”

“…and phosphatidylcholines have been shown to be efficiently transferred by LTPs (Kader, 1996a). X-ray crystallographic and 1 H-NMR analysis of several plant LTPs has demonstrated that they can accommodate only one acyl chain into their binding tunnel without major disturbance in the tertiary structure of the proteins (Gincel et al, 1994; Heinemann et al, 1996;Shin et al, 1995). Therefore, the second acyl chain attached to position 2 of glycerol was modelled on the surface of BLT4.9.…”

“…The three-dimensional tertiary structure of a maize seedling LTP has been resolved by X-ray crystallography (Shin et al, 1995) and two cereal seed LTPs (wheat, Gincel et al, 1994;barley, Heinemann et al, 1996) by threedimensional 1 H-NMR. These 3 proteins have a similar structure, in which four α-helices (stabilized by four disulphide bridges) enclose an internal hydrophobic cavity.…”

Structure in solution of a four‐helix lipid binding protein

“…Recently, the three-dimensional crystal structures of maize nsLTP (mLTP) and the complex with palmitate (Shin et al, 1995) were reported, and so was the solution structure of wheat nsLTP (wLTP) (Gincel et al, 1995). These LTPs are four-helix proteins, and mLTP is shown to bind palmitate in an extended form in a hydrophobic cavity in the four-helix protein.…”