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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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Distinctly dual charge character of PfUIS3130-229. a and b, electrostatic surface representation of PfUIS3 in orthogonal views showing the negative charge patch (a) and the conserved positively charged cluster (b). The surface is colored blue for potentials >10 kT/e and red for potentials <-10 kT/e.
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fig4: Distinctly dual charge character of PfUIS3130-229. a and b, electrostatic surface representation of PfUIS3 in orthogonal views showing the negative charge patch (a) and the conserved positively charged cluster (b). The surface is colored blue for potentials >10 kT/e and red for potentials <-10 kT/e.

Mentions: The superposition of Cα atoms of the six monomers (A to F) of PfUIS3130-229 in the asymmetric unit gives an root mean square deviation of ∼0.5 Å. There is no noncrystallographic point group symmetry found between the six PfUIS3130-229 protomers. Interestingly, the protomer arrangements reveal two independent helical motifs (-A-C-F-A-C-F- and -B-D-E-B-D-E-) along the crystallographic b-axis. The thickness of the helix is ∼67 Å with inner and outer diameters of ∼43 and ∼110 Å, respectively. PfUIS3130-229 monomers AB, CD, EE′, and FF′ are related by ∼180° (E′ and F′ are symmetry equivalent molecules). There are two different sets of intermolecular interactions: (a) between A and B, C and D, E and E′, and F and F′ and (b) between B and E and D and F. PfUIS3 has dimensions of ∼44 × 29 × 23 Å and adopts a globular fold of four α-helices that pack against each other tightly. Residues from 130-148 form a random coil (C1) at the N terminus, and this is followed by an α-helix (H1, residues 149-169). A tight turn T1 (170-171) separates α-helix H2 (172-178) from α-helix H1. Another turn T2 (179-181) connects α-helix H2 with α-helix H3 (182-196). Finally, turn T3 (197-201) connects α-helix H3 to terminal α-helix H4 (202-227) (Fig. 2). PfUIS3130-229 fold is highly reminiscent of the ubiquitous helix-turn-helix motifs, and sequence comparison of UIS3 homologs from various plasmodial species suggests a high level of conservation (Fig. 3). The PfUIS3 surface has a spatially distinct opposite charge character. A broad negatively charged patch is evident on one face of PfUIS3130-229, which contains many charged residues, particularly Glu228, Glu227, Asp176, and Asp173 (Fig. 4a). Distal to this acidic cluster is a channel of basic residues: Lys150, Arg151, Arg196, Lys165, and Lys131 (Fig. 4b).


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)

Distinctly dual charge character of PfUIS3130-229. a and b, electrostatic surface representation of PfUIS3 in orthogonal views showing the negative charge patch (a) and the conserved positively charged cluster (b). The surface is colored blue for potentials >10 kT/e and red for potentials <-10 kT/e.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig4: Distinctly dual charge character of PfUIS3130-229. a and b, electrostatic surface representation of PfUIS3 in orthogonal views showing the negative charge patch (a) and the conserved positively charged cluster (b). The surface is colored blue for potentials >10 kT/e and red for potentials <-10 kT/e.
Mentions: The superposition of Cα atoms of the six monomers (A to F) of PfUIS3130-229 in the asymmetric unit gives an root mean square deviation of ∼0.5 Å. There is no noncrystallographic point group symmetry found between the six PfUIS3130-229 protomers. Interestingly, the protomer arrangements reveal two independent helical motifs (-A-C-F-A-C-F- and -B-D-E-B-D-E-) along the crystallographic b-axis. The thickness of the helix is ∼67 Å with inner and outer diameters of ∼43 and ∼110 Å, respectively. PfUIS3130-229 monomers AB, CD, EE′, and FF′ are related by ∼180° (E′ and F′ are symmetry equivalent molecules). There are two different sets of intermolecular interactions: (a) between A and B, C and D, E and E′, and F and F′ and (b) between B and E and D and F. PfUIS3 has dimensions of ∼44 × 29 × 23 Å and adopts a globular fold of four α-helices that pack against each other tightly. Residues from 130-148 form a random coil (C1) at the N terminus, and this is followed by an α-helix (H1, residues 149-169). A tight turn T1 (170-171) separates α-helix H2 (172-178) from α-helix H1. Another turn T2 (179-181) connects α-helix H2 with α-helix H3 (182-196). Finally, turn T3 (197-201) connects α-helix H3 to terminal α-helix H4 (202-227) (Fig. 2). PfUIS3130-229 fold is highly reminiscent of the ubiquitous helix-turn-helix motifs, and sequence comparison of UIS3 homologs from various plasmodial species suggests a high level of conservation (Fig. 3). The PfUIS3 surface has a spatially distinct opposite charge character. A broad negatively charged patch is evident on one face of PfUIS3130-229, which contains many charged residues, particularly Glu228, Glu227, Asp176, and Asp173 (Fig. 4a). Distal to this acidic cluster is a channel of basic residues: Lys150, Arg151, Arg196, Lys165, and Lys131 (Fig. 4b).

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