The hydrophobic surface of PaAMP from pokeweed seeds is essential to its interaction with fungal membrane lipids and the antifungal activity.
PaAMP is a small seed-specific antimicrobial protein from pokeweeds. It has a cysteine-knot fold with a positive patch and a hydrophobic surface. Site-specific mutagenesis was performed to study the roles of these two domains in antimicrobial activity and we found that the mutations in the hydrophobic surface had a more profound effect than that in the positive patch. A protein-membrane interaction was observed with the green fluorescence protein-PaAMP (GFP-AMP) fusion protein. The mutations that replace the amino acid residues forming hydrophobic surface with neutral residues abolished the interaction of PaAMP with the membrane and the binding of PaAMP to fungal sphingolipids while ergosterol enhanced the binding, suggesting that the hydrophobic surface was required for the interaction between PaAMP and fungal plasma membrane lipid raft.
Peng
Cheng
C
State Key Laboratory of Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing, China.
Dong
Chunxia
C
Hou
Qiaomin
Q
Xu
Chunyu
C
Zhao
Jindong
J
D000935:Antifungal Agents / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology*; D005670:Fusarium / Q000187:drug effects; D057927:Hydrophobic and Hydrophilic Interactions; D020128:Inhibitory Concentration 50; D008563:Membrane Lipids / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D009492:Neurospora crassa / Q000187:drug effects; D029604:Phytolacca americana / Q000737:chemistry* / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D012639:Seeds / Q000737:chemistry* / Q000235:genetics
D000935:Antifungal Agents; D008563:Membrane Lipids; D010940:Plant Proteins; D011994:Recombinant Proteins