title: Characterization of the GPI-anchored lipid transfer proteins in the moss Physcomitrella patens.
abstract: The non-specific lipid transfer proteins (nsLTPs) are characterized by a compact structure with a central hydrophobic cavity very suitable for binding hydrophobic ligands, such as lipids. The nsLTPs are encoded by large gene families in all land plant lineages, but seem to be absent from green algae. The nsLTPs are classified to different types based on molecular weight, sequence similarity, intron position or spacing between the cysteine residues. The Type G nsLTPs (LTPGs) have a GPI-anchor in the C-terminal region which may attach the protein to the exterior side of the plasma membrane. Here, we present the first characterization of nsLTPs from an early diverged plant, the moss Physcomitrella patens. Moss LTPGs were heterologously produced and purified from Pichia pastoris. The purified moss LTPGs were found to be extremely heat stable and showed a binding preference for unsaturated fatty acids. Structural modeling implied that high alanine content could be important for the heat stability. Lipid profiling revealed that cutin monomers, such as C16 and C18 mono- and di-hydroxylated fatty acids, could be identified in P. patens. Expression of a moss LTPG-YFP fusion revealed localization to the plasma membrane. The expressions of many of the moss LTPGs were found to be upregulated during drought and cold treatments.
authors.affiliation: IFM, Linköping University, 581 83 Linköping, Sweden.
authors.forename: Monika M
authors.initials: MM
authors.lastname: Edstam
authors.affiliation: Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland.
authors.forename: Maiju
authors.initials: M
authors.lastname: Laurila
authors.affiliation: IFM, Linköping University, 581 83 Linköping, Sweden.
authors.forename: Andrey
authors.initials: A
authors.lastname: Höglund
authors.affiliation: IFM, Linköping University, 581 83 Linköping, Sweden.
authors.forename: Amitha
authors.initials: A
authors.lastname: Raman
authors.affiliation: Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland.
authors.forename: Käthe M
authors.initials: KM
authors.lastname: Dahlström
authors.affiliation: Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland.
authors.forename: Tiina A
authors.initials: TA
authors.lastname: Salminen
authors.affiliation: IFM, Linköping University, 581 83 Linköping, Sweden. Electronic address: Johan.Edqvist@liu.se.
authors.forename: Johan
authors.initials: J
authors.lastname: Edqvist
authors.affiliation: IFM, Linköping University, 581 83 Linköping, Sweden.
authors.forename: Kristina
authors.initials: K
authors.lastname: Blomqvist
mesh_terms: D000409:Alanine / Q000378:metabolism; D000595:Amino Acid Sequence; D019068:Bryopsida / Q000737:chemistry / Q000378:metabolism*; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003080:Cold Temperature; D055864:Droughts; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D058851:GPI-Linked Proteins / Q000737:chemistry / Q000378:metabolism*; D057927:Hydrophobic and Hydrophilic Interactions; D008563:Membrane Lipids / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D013312:Stress, Physiological; D015854:Up-Regulation
chemical_list: D002352:Carrier Proteins; D005231:Fatty Acids, Unsaturated; D058851:GPI-Linked Proteins; D008563:Membrane Lipids; D010940:Plant Proteins; C030363:lipid transfer protein; C000521:cutin; D000409:Alanine
keywords: Circular dichroism; Cuticle; Cutin; Heat stability; LTP; Lipids; Moss