Plant lipid transfer proteins
About: Plant lipid transfer proteins is a research topic. Over the lifetime, 1027 publications have been published within this topic receiving 47469 citations.
Papers published on a yearly basis
••01 Jun 1996
TL;DR: Novel roles were suggested for plant LTPs: participation in cutin formation, embryogenesis, defense reactions against phytopathogens, symbiosis, and the adaptation of plants to various environmental conditions.
Abstract: Lipid-transfer proteins (LTP) are basic, 9-kDa proteins present in high amounts (as much as 4% of the total soluble proteinss) in higher plants. LTPs can enhance the in vitro transfer of phospholipids between membranes and can bind acyl chains. On the basis of these properties, LTPs were thought to participate in membrane biogenesis and regulation of the intracellular fatty acid pools. However, the isolation of several cDNAs and genes revealed the presence of a signal peptide indicating that LTPs could enter the secretory pathway. They were found to be secreted and located in the cell wall. Thus, novel roles were suggested for plant LTPs: participation in cutin formation, embryogenesis, defense reactions against phytopathogens, symbiosis, and the adaptation of plants to various environmental conditions. The validity of these suggestions needs to be determined, in the hope that they will elucidate the role of this puzzling family of plant proteins.
TL;DR: Allergens have no characteristic structural features other than that they need to be able to reach (and stimulate) immune cells and mast cells, and within this constraint, any antigen may be allergenic, particularly if it avoids activation of T(H)2-suppressive mechanisms.
Abstract: One of the major challenges of molecular allergy is to predict the allergenic potential of a protein, particularly in novel foods. Two aspects have to be distinguished: immunogenicity and cross-reactivity. Immunogenicity reflects the potential of a protein to induce IgE antibodies, whereas cross-reactivity is the reactivity of (usually preexisting) IgE antibodies with the target protein. In addition to these two issues, the relation between IgE-binding potential and clinical symptoms is of interest. This is influenced by physical properties (eg, stability and size) and immunologic properties (affinity and epitope valence). Discussions on immunogenicity and cross-reactivity of allergens rely on the establishment of structural similarities and differences among allergens and between allergens and nonallergens. For comparisons between the 3-dimensional protein folds, the representation as 2-dimensional proximity plots provides a convenient visual aid. Analysis of approximately 40 allergenic proteins (or parts of these proteins), of which the protein folds are either known or can be predicted on the basis of homology, indicates that most of these can be classified into 4 structural families: (1) antiparallel beta-strands: the immunoglobulin-fold family (grass group 2, mite group 2), serine proteases (mite group 3, 6, and 9), and soybean-type trypsin inhibitor (Ole e 1, grass group 11); (2) antiparallel beta-sheets intimately associated with one or more alpha-helices: tree group 1, lipocalin, profilin, aspartate protease (cockroach group 2); (3) (alpha+beta) structures, in which the alpha- and beta-structural elements are not intimately associated: mite group 1, lysozyme/lactalbumin, vespid group 5; and (4) alpha-helical: nonspecific lipid transfer protein, seed 2S protein, insect hemoglobin, fish parvalbumin, pollen calmodulin, mellitin from bee venom, Fel d 1 chain 1, serum albumin. Allergens with parallel beta-strands (in combination with an alpha-helix linking the two strands, a motif commonly found in, for example, nucleotide-binding proteins) seem to be underrepresented. The conclusion is that allergens have no characteristic structural features other than that they need to be able to reach (and stimulate) immune cells and mast cells. Within this constraint, any antigen may be allergenic, particularly if it avoids activation of T(H)2-suppressive mechanisms (CD8 cells and T(H)1 cells).
TL;DR: OSBP-mediated back transfer of PI(4)P might coordinate the transfer of other lipid species at the ER-Golgi interface, suggesting the ability to both tether organelles and transport lipids between them.
Abstract: Several proteins at endoplasmic reticulum (ER)-Golgi membrane contact sites contain a PH domain that interacts with the Golgi phosphoinositide PI(4)P, a FFAT motif that interacts with the ER protein VAP-A, and a lipid transfer domain. This architecture suggests the ability to both tether organelles and transport lipids between them. We show that in oxysterol binding protein (OSBP) these two activities are coupled by a four-step cycle. Membrane tethering by the PH domain and the FFAT motif enables sterol transfer by the lipid transfer domain (ORD), followed by back transfer of PI(4)P by the ORD. Finally, PI(4)P is hydrolyzed in cis by the ER protein Sac1. The energy provided by PI(4)P hydrolysis drives sterol transfer and allows negative feedback when PI(4)P becomes limiting. Other lipid transfer proteins are tethered by the same mechanism. Thus, OSBP-mediated back transfer of PI(4)P might coordinate the transfer of other lipid species at the ER-Golgi interface.
14 Nov 1996
TL;DR: This chapter discusses Solubility, Emulsifying Properties of Proteins, and the Mechanism of Protein-Water Interaction as well as investigating the role of protein concentration in the development of emulsifying properties.
Abstract: References.- 1 Solubility of Proteins.- 1.1 Introduction.- 1.1.1 Factors Affecting Solubility of Proteins.- 1.2 Solubility of Meat and Fish Proteins.- 1.2.1 Solubility of Muscle Proteins.- 1.2.2 Solubility of Stroma Proteins.- 1.2.3 Protein Solubility in Processed Meats.- 1.2.4 Solubility of Blood Proteins.- 1.2.5 The Effect of Heating on Solubility of Proteins.- 1.2.6 The Effect of Freezing and Storage When Frozen on Protein Solubility.- 1.2.7 The Effect of Protein Modification and Irradiation Treatment.- 1.3 Solubility of Milk Proteins.- 1.4 Solubility of Egg Proteins.- 1.5 Solubility of Plant Proteins.- 1.5.1 Soybean Proteins.- 1.5.2 Peanut Proteins.- 1.5.3 Pea and Bean Proteins.- 1.5.4 Sunflower Proteins.- 1.5.5 Corn Proteins.- 1.5.6 Miscellaneous Plant Proteins.- References.- 2 Water Holding Capacity of Proteins.- 2.1 Introduction.- 2.2 The Mechanism of Protein-Water Interaction.- 2.2.1 Factors Influencing Water Binding of Proteins.- 2.3 Water Holding Capacity of Proteins in Meat and Meat Products.- 2.3.1 Water Binding Capacity of Muscle Proteins.- 2.3.2 Factors Influencing Water Binding of Muscle Proteins.- 2.3.3 Water Binding in Comminuted Meat Products.- 2.3.4 Milk Proteins in Comminuted Meats.- 2.3.5 Soy Proteins in Comminuted Meats.- 2.3.6 Corn Germ Protein in Comminuted Meats.- 2.4 Water Holding Capacity of Milk Proteins.- 2.5 Water Holding Capacity of Egg Proteins.- 2.6 Water Holding Capacity of Plant Proteins.- 2.6.1 Soybean Proteins.- 2.6.2 Pea and Bean Proteins.- 2.6.3 Sunflower Proteins.- 2.6.4 Corn Proteins.- 2.6.5 Wheat Proteins.- 2.6.6 Miscellaneous Proteins.- References.- 3 Emulsifying Properties of Proteins.- 3.1 Introduction.- 3.2 Hydrophobic and Hydrophilic Properties of Proteins.- 3.3 Interfacial Film Formation and Properties.- 3.4 Factors Affecting the Emulsifying Properties of Proteins.- 3.4.1 Protein Concentration.- 3.4.2 pH of Medium.- 3.4.3 Ionic Strength.- 3.4.4 Heat Treatment and Other Factors.- 3.5 Emulsion Stability.- 3.6 Measuring Emulsifying Properties.- 3.7 Emulsifying Properties of Meat Proteins and Proteins Utilized as Extenders in Meat Products.- 3.7.1 Protein Functionality in Comminuted Meats.- 3.7.2 Emulsifying Properties of Various Muscular Proteins.- 3.7.3 Emulsifying Properties of Blood Proteins.- 3.8 Functionality of Nonmeat Proteins in Comminuted Meats.- 3.8.1 Milk Proteins.- 3.8.2 Soy Proteins.- 3.8.3 Corn and Wheat Germ Proteins.- 3.9 Milk Proteins as Emulsifiers in Food Systems.- 3.9.1 Emulsifying Properties of Caseins and Caseinates.- 3.9.2 Emulsifying Properties of Whey Proteins.- 3.10 Emulsifying Properties of Egg Proteins.- 3.11 Emulsifying Properties of Plant Proteins.- 3.11.1 Soybean Proteins.- 3.11.2 Pea and Bean Proteins.- 3.11.3 Corn Proteins.- 3.11.4 Miscellaneous Proteins.- References.- 4 Oil and Fat Binding Properties Of Proteins.- 4.1 Introduction.- 4.2 Fat Binding Properties of Proteins of Animal Origin.- 4.2.1 Muscle Proteins.- 4.2.2 Soy Proteins in Comminuted Meats.- 4.2.3 The Effect of Corn Germ Protein Flour on Fat Binding in Ground Beef Patties.- 4.2.4 Milk and Egg Proteins.- 4.3 Fat Binding Properties of Proteins of Plant Origin.- 4.3.1 Soy Proteins.- 4.3.2 Pea, Bean and Guar Proteins.- 4.3.3 Corn Germ Proteins.- 4.3.4 Wheat Proteins.- 4.3.5 Cottonseed Proteins.- 4.3.6 Miscellaneous Proteins.- References.- 5 Foaming Properties of Proteins.- 5.1 Introduction.- 5.2 The Mechanism of Foam Formation.- 5.2.1 Factors Affecting Foam Formation.- 5.2.2 Foam Stability.- 5.3 Milk Proteins.- 5.3.1 Factors Affecting the Foaming Properties of Milk Proteins.- 5.4 Egg Proteins.- 5.4.1 The Effect of Processing on Foaming Properties of Egg Proteins.- 5.5 Blood Proteins and Gelatin.- 5.6 The Foaming Properties of Plant Proteins.- References.- 6 Gelling Properties of Proteins.- 6.1 Introduction.- 6.2 The Mechanism of Protein Gel Formation.- 6.2.1 Heat-Induced Gelation.- 6.2.2 Protein-Water Interaction in Gels.- 6.2.3 Factors Affecting the Properties of Gels.- 6.3 Gelling Properties of Meat Proteins.- 6.3.1 Myofibrillar Proteins.- 6.3.2 Sarcoplasmic Proteins.- 6.3.3 Gelation of Red and White Muscle Proteins.- 6.3.4 Factors Affecting the Gelling Properties of Meat Proteins.- 6.3.5 Myosin Blends with Other Proteins and Lipids.- 6.3.6 Fish Proteins.- 6.3.7 Collagen Gelation.- 6.3.8 Blood Proteins.- 6.4 Gelling Properties of Milk Proteins.- 6.4.1 Gelling Properties of Whey Protein Concentrate, Isolate, and Individual hey Proteins.- 6.4.2 The Effect of Heating and Protein Concentration.- 6.4.3 Gelation of Casein.- 6.4.4 Factors Affecting the Gelling Properties of Milk Proteins.- 6.5 Gelling Properties of Egg Proteins.- 6.5.1 Gelation of Egg White.- 6.5.2 Gelation of Yolk.- 6.6 Gelling Properties of Soy Proteins.- References.
TL;DR: Allergens other than PR homologs can be allotted to other well-known protein families such as inhibitors of alpha-amylases and trypsin from cereal seeds, profilins from fruits and vegetables, seed storage proteins from nuts and mustard seeds, and proteases from fruits.
Abstract: Molecular biology and biochemical techniques have significantly advanced the knowledge of allergens derived from plant foods. Surprisingly, many of the known plant food allergens are homologous to pathogenesis-related proteins (PRs), proteins that are induced by pathogens, wounding, or certain environmental stresses. PRs have been classified into 14 families. Examples of allergens homologous to PRs include chitinases (PR-3 family) from avocado, banana, and chestnut; antifungal proteins such as the thaumatin-like proteins (PR-5) from cherry and apple; proteins homologous to the major birch pollen allergen Bet v 1 (PR-10) from vegetables and fruits; and lipid transfer proteins (PR-14) from fruits and cereals. Allergens other than PR homologs can be allotted to other well-known protein families such as inhibitors of α-amylases and trypsin from cereal seeds, profilins from fruits and vegetables, seed storage proteins from nuts and mustard seeds, and proteases from fruits. As more clinical data and structural information on allergenic molecules becomes available, we may finally be able to answer what characteristics of a molecule are responsible for its allergenicity. (J Allergy Clin Immunol 2000;106:27-36.)
Trending Questions (5)
Related Topics (5)