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

Sharma A, Yogavel M, Akhouri RR, Gill J, Sharma A - J. Biol. Chem. (2008)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Structural and Computational Biology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Road, New Delhi, India.

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.

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Dynamic light scattering studies of PfUIS3130-229-liposome complexes. a, a distinct increase in the hydrodynamic radii of liposomes was observed with the addition of PfUIS3130-229-indicating assembly and decoration of liposomes with PfUIS3130-229. b, no such shift in molecular size of liposomes was observed with control proteins like BSA (and others; data not shown).
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fig9: Dynamic light scattering studies of PfUIS3130-229-liposome complexes. a, a distinct increase in the hydrodynamic radii of liposomes was observed with the addition of PfUIS3130-229-indicating assembly and decoration of liposomes with PfUIS3130-229. b, no such shift in molecular size of liposomes was observed with control proteins like BSA (and others; data not shown).

Mentions: PfUIS3130-229 Interaction with Fatty Acids and Liposomes—PfUIS3130-229-lipid/fatty acid interactions were further probed using two independent biophysical techniques. We performed CD experiments using far UV (240-190 nm) on purified PfUIS3130-229 (monomer)-liposome complexes. A titration study indicated distinct and specific conformational changes in PfUIS3130-229 in the presence of liposomes (Fig. 8a). Interaction with liposomes seems to decrease the helical content of PfUIS3130-229 in favor of random coil (Fig. 8, a and b), suggesting increased disorder in the protein. A plot of ellipticity as a function of liposome concentration at 208 nm (Fig. 8c) and 222 nm (Fig. 7d) emphasizes this conformational shift. To probe whether PfUIS3130-229 interaction with liposomes resulted in sequestration of PfUIS3130-229 onto liposomes, we used dynamic light scattering as a probe of molecular size distribution in PfUIS3130-229-liposome complexes. As shown in Fig. 9, an increase in the hydrodynamic radius of liposomes was observed as a function of PfUIS3130-229 concentration. Enlargement of liposome upon PfUIS3130-229 engagement indicates specific complex formation between the two and possible sequestration of multiple molecules of PfUIS3130-229 on the liposome surface. Such liposome decoration with PfUIS3130-229 may mimic the interaction of PfUIS3130-229 with parasite PVM, an event likely to facilitate transfer of fatty acid/lipid cargo directly on to the parasite membrane.


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

Sharma A, Yogavel M, Akhouri RR, Gill J, Sharma A - J. Biol. Chem. (2008)

Dynamic light scattering studies of PfUIS3130-229-liposome complexes. a, a distinct increase in the hydrodynamic radii of liposomes was observed with the addition of PfUIS3130-229-indicating assembly and decoration of liposomes with PfUIS3130-229. b, no such shift in molecular size of liposomes was observed with control proteins like BSA (and others; data not shown).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2527117&req=5

fig9: Dynamic light scattering studies of PfUIS3130-229-liposome complexes. a, a distinct increase in the hydrodynamic radii of liposomes was observed with the addition of PfUIS3130-229-indicating assembly and decoration of liposomes with PfUIS3130-229. b, no such shift in molecular size of liposomes was observed with control proteins like BSA (and others; data not shown).
Mentions: PfUIS3130-229 Interaction with Fatty Acids and Liposomes—PfUIS3130-229-lipid/fatty acid interactions were further probed using two independent biophysical techniques. We performed CD experiments using far UV (240-190 nm) on purified PfUIS3130-229 (monomer)-liposome complexes. A titration study indicated distinct and specific conformational changes in PfUIS3130-229 in the presence of liposomes (Fig. 8a). Interaction with liposomes seems to decrease the helical content of PfUIS3130-229 in favor of random coil (Fig. 8, a and b), suggesting increased disorder in the protein. A plot of ellipticity as a function of liposome concentration at 208 nm (Fig. 8c) and 222 nm (Fig. 7d) emphasizes this conformational shift. To probe whether PfUIS3130-229 interaction with liposomes resulted in sequestration of PfUIS3130-229 onto liposomes, we used dynamic light scattering as a probe of molecular size distribution in PfUIS3130-229-liposome complexes. As shown in Fig. 9, an increase in the hydrodynamic radius of liposomes was observed as a function of PfUIS3130-229 concentration. Enlargement of liposome upon PfUIS3130-229 engagement indicates specific complex formation between the two and possible sequestration of multiple molecules of PfUIS3130-229 on the liposome surface. Such liposome decoration with PfUIS3130-229 may mimic the interaction of PfUIS3130-229 with parasite PVM, an event likely to facilitate transfer of fatty acid/lipid cargo directly on to the parasite membrane.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Structural and Computational Biology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Road, New Delhi, India.

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.

Show MeSH
Related in: MedlinePlus