Crystal structure of soluble domain of malaria sporozoite protein UIS3 in complex with lipid

J Biol Chem. 2008 Aug 29;283(35):24077-88. doi: 10.1074/jbc.M801946200. Epub 2008 Jun 23.

Abstract

Malaria parasite UIS3 (up-regulated in infective sporozoites gene 3) is essential for sporozoite development in infected hepatocytes. UIS3 encodes for a membrane protein that is localized to the parasite parasitophorous vacuolar membrane in infected hepatocytes. We describe here 2.5-A resolution crystal structure of Plasmodium falciparum UIS3 soluble domain (PfUIS3(130-229)) in complex with the lipid phosphatidylethanolamine (PE). PfUIS3(130-229) is a novel, compact, and all alpha-helical structure bound to one molecule of PE. The PfUIS3(130-229)-PE complex structure reveals a novel binding site with specific interactions between PfUIS3(130-229) and the PE head group. One acyl chain of PE wraps around part of PfUIS3(130-229) and docks onto a hydrophobic channel. We additionally provide new structural and biochemical evidence of PfUIS3(130-229) interactions with lipids (phosphatidylethanolamine), with phospholipid liposomes, and with the human liver fatty acid-binding protein. The direct interaction of PfUIS3(130-229) with liver fatty acid-binding protein most likely provides the parasite with a conduit for importing essential fatty acids/lipids. Therefore, our analyses have implications for lipid transport into the parasite during the rapid growth phases of sporozoites. Given that PfUIS3 is essential for establishment of liver stage infection by P. falciparum, our data provide a new target for abrogating parasite development within liver cells before typical symptoms of malaria can manifest.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Crystallography, X-Ray
  • Fatty Acid-Binding Proteins / chemistry
  • Fatty Acid-Binding Proteins / genetics
  • Fatty Acid-Binding Proteins / metabolism
  • Hepatocytes / metabolism
  • Hepatocytes / parasitology
  • Humans
  • Hydrophobic and Hydrophilic Interactions
  • Liver / metabolism
  • Liver / parasitology
  • Membrane Proteins / chemistry*
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Phosphatidylethanolamines / chemistry*
  • Phosphatidylethanolamines / genetics
  • Phosphatidylethanolamines / metabolism
  • Plasmodium falciparum / chemistry*
  • Plasmodium falciparum / genetics
  • Plasmodium falciparum / metabolism
  • Protein Structure, Secondary / physiology
  • Protein Structure, Tertiary / physiology
  • Protozoan Proteins / chemistry*
  • Protozoan Proteins / genetics
  • Protozoan Proteins / metabolism
  • Solubility

Substances

  • Fatty Acid-Binding Proteins
  • Membrane Proteins
  • Phosphatidylethanolamines
  • Protozoan Proteins
  • UIS3 protein, Plasmodium falciparum
  • phosphatidylethanolamine

Associated data

  • PDB/2VWA