K-Segment of Maize DHN1 Mediates Binding to Anionic Phospholipid Vesicles and Concomitant Structural Changes

• Published in: Plant physiology (Bethesda) Vol. 150; no. 3; pp. 1503 - 1514
• Main Authors: Koag, Myong-Chul, Wilkens, Stephan, Fenton, Raymond D, Resnik, Josh, Vo, Evanly, Close, Timothy J
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Biologists 01.07.2009
• Subjects: Amino Acid Sequence; Amino acids; Biochemical Processes and Macromolecular Structures; Biological and medical sciences; Cell membranes; Consensus Sequence; Corn; Cytoplasmic Vesicles - metabolism; Escherichia coli - genetics; Fundamental and applied biological sciences. Psychology; Lipids; Liposomes; Liposomes - metabolism; Molecular Sequence Data; Mutant proteins; Phospholipids; Phospholipids - metabolism; Phosphorylation; Plant cells; Plant physiology and development; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - physiology; Protein Structure, Tertiary; Proteins; Seeds - growth & development; Seeds - metabolism; Sodium Dodecyl Sulfate - pharmacology; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Zea mays - metabolism; Zea mays - ultrastructure; Vesicle; Monocotyledones; Zea mays; Plant physiology; Gramineae; Angiospermae; Phospholipid; Structure modification; Spermatophyta; Cereal crop
• ISSN: 0032-0889; 1532-2548; 1532-2548
• DOI: 10.1104/pp.109.136697

Dehydrins (DHNs; late embryogenesis abundant D11 family) are a family of intrinsically unstructured plant proteins that accumulate in the late stages of seed development and in vegetative tissues subjected to water deficit, salinity, low temperature, or abscisic acid treatment. We demonstrated previously that maize (Zea mays) DHNs bind preferentially to anionic phospholipid vesicles; this binding is accompanied by an increase in α-helicity of the protein, and adoption of α-helicity can be induced by sodium dodecyl sulfate. All DHNs contain at least one "K-segment," a lysine-rich 15-amino acid consensus sequence. The K-segment is predicted to form a class A2 amphipathic α-helix, a structural element known to interact with membranes and proteins. Here, three K-segment deletion proteins of maize DHN1 were produced. Lipid vesicle-binding assays revealed that the K-segment is required for binding to anionic phospholipid vesicles, and adoption of α-helicity of the K-segment accounts for most of the conformational change of DHNs upon binding to anionic phospholipid vesicles or sodium dodecyl sulfate. The adoption of structure may help stabilize cellular components, including membranes, under stress conditions.