Solution structure of a tobacco lipid transfer protein exhibiting new biophysical and biological features

• DOI: 10.1002/prot.20405
• Publication Date: 2005-02-22T21:47:34Z
• Authors: Pedro Da Silva; Céline Landon; Benoit Industri; Antoine Marais; Didier Marion; Michel Ponchet; Françoise Vovelle
• Keywords: Models, Molecular; Nicotiana; 0301 basic medicine; Magnetic Resonance Spectroscopy; [SPI.GPROC] Engineering Sciences [physics]/Chemical and Process Engineering; Protein Conformation; Molecular Sequence Data; MODELISATION MOLECULAIRE; 03 medical and health sciences; HYDROPHOBIC CAVITY; [SDV.IDA]Life Sciences [q-bio]/Food engineering; [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering; DNA Primers; Plant Proteins; 2. Zero hunger; TOBACCO; 0303 health sciences; Base Sequence; Nitrogen Isotopes; CYSTEINE RICH PROTEIN; [SDV.IDA] Life Sciences [q-bio]/Food engineering; Antigens, Plant; ORTHOGONAL BUNDLE; Recombinant Proteins; Biomechanical Phenomena; Solutions; LTP; PROTEINE DE TRANSFERT DE LIPIDE; Carrier Proteins

AbstractPlant lipid transfer proteins are small soluble extracellular proteins that are able to bind and transfer a variety of lipidsin vitro. Recently, it has been proposed that lipid transfer proteins may play a key role in plant defence mechanisms, especially during the induction of systemic acquired resistance. However, very little is known about the proteins expressed in developing plants and tissues, since almost all the biophysical and structural data available to date on lipid transfer proteins originate from proteins present in storage tissues of monocot cereal seeds. In this paper, we report the structural and functional characteristics of a lipid transfer protein (named LTP1_1) constitutively expressed in young aerial organs ofNicotiana tabacum(common tobacco). The unlabelled and uniformly labelled proteins were produced in the yeastPichia pastoris, and we determined the three‐dimensional (3D) structure of LTP1_1 using nuclear magnetic resonance (NMR) spectroscopy and molecular modeling techniques. The global fold of LTP1_1 is very close to the previously published structures of LTP1 extracted from cereal seeds, including an internal cavity. However, the chemical shift variations of several NMR signals upon lipid binding show that tobacco LTP1_1 is able to bind only one LysoMyristoylPhosphatidylCholine (LMPC), while wheat and maize LTPs can bind either one or two. Titration experiments using intrinsic tyrosine fluorescence confirm this result not only with LMPC but also with two fatty acids. These differences can be explained by the presence in tobacco LTP1_1 of a hydrophobic cluster closing the second possible access to the protein cavity. This result suggests that LTP1 lipid binding properties could be modulated by subtle changes in a conserved global structure. The biological significance of this finding is discussed in the light of the signalling properties of the tobacco LTP1_1–jasmonate complex described elsewhere.1Proteins 2005. © 2005 Wiley‐Liss, Inc.