The K-segment of maize DHN1 mediates binding to anionic phospholipid vesicles and concomitant structural changes.
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 alpha-helicity of the protein, and adoption of alpha-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 alpha-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 alpha-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.
Koag
Myong-Chul
MC
Graduate Program in Biochemistry and Molecular Biology, University of California, Riverside, California 92521-0124, USA.
Wilkens
Stephan
S
Fenton
Raymond D
RD
Resnik
Josh
J
Vo
Evanly
E
Close
Timothy J
TJ
D000595:Amino Acid Sequence; D016384:Consensus Sequence; D022162:Cytoplasmic Vesicles / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D008081:Liposomes / Q000378:metabolism; D008969:Molecular Sequence Data; D010743:Phospholipids / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D017434:Protein Structure, Tertiary; D012639:Seeds / Q000254:growth & development / Q000378:metabolism; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D003313:Zea mays / Q000378:metabolism* / Q000648:ultrastructure
D008081:Liposomes; D010743:Phospholipids; D010940:Plant Proteins; C070556:dehydrin proteins, plant; D012967:Sodium Dodecyl Sulfate