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Vitamin B6 biosynthesis by the malaria parasite Plasmodium falciparum: biochemical and structural insights

Vitamin B6 biosynthesis by the malaria parasite Plasmodium falciparum: biochemical and structural insights
Vitamin B6 biosynthesis by the malaria parasite Plasmodium falciparum: biochemical and structural insights
Vitamin B6 is one of nature's most versatile cofactors. Most organisms synthesize vitamin B6 via a recently discovered pathway employing the proteins Pdx1 and Pdx2. Here we present an in-depth characterization of the respective orthologs from the malaria parasite, Plasmodium falciparum. Expression profiling of Pdx1 and -2 shows that blood-stage parasites indeed possess a functional vitamin B6 de novo biosynthesis. Recombinant Pdx1 and Pdx2 form a complex that functions as a glutamine amidotransferase with Pdx2 as the glutaminase and Pdx1 as pyridoxal-5 '-phosphate synthase domain. Complex formation is required for catalytic activity of either domain. Pdx1 forms a chimeric bi-enzyme with the bacterial YaaE, a Pdx2 ortholog, both in vivo and in vitro, although this chimera does not attain full catalytic activity, emphasizing that species-specific structural features govern the interaction between the protein partners of the PLP synthase complexes in different organisms. To gain insight into the activation mechanism of the parasite bi-enzyme complex, the three-dimensional structure of Pdx2 was determined at 1.62 A. The obstruction of the oxyanion hole indicates that Pdx2 is in a resting state and that activation occurs upon Pdx1-Pdx2 complex formation.
0021-9258
3633-3641
Gengenbacher, Martin
0d3f66c3-f327-488b-93ad-6070366e0f73
Fitzpatrick, Teresa B
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Raschle, Thomas
72f8f1f6-516f-4610-a14b-5b82ea03204f
Flicker, Karlheinz
2d14a029-e083-4424-80c1-c6b83b5bd345
Sinning, Irmgard
fbc3f199-8a3b-47a6-9ee7-00bfc472e079
Müller, Sylke
bebf2a17-a17d-4200-a19c-694dc5b086a6
Macheroux, Peter
e1c49266-c971-42f7-86ae-394bd128d040
Tews, Ivo
9117fc5e-d01c-4f8d-a734-5b14d3eee8dd
Kappes, Barbara
10edf779-dc81-4973-878b-d3177273f86a
Gengenbacher, Martin
0d3f66c3-f327-488b-93ad-6070366e0f73
Fitzpatrick, Teresa B
ba3eee8b-d3e5-4a18-9845-64f5e56962f5
Raschle, Thomas
72f8f1f6-516f-4610-a14b-5b82ea03204f
Flicker, Karlheinz
2d14a029-e083-4424-80c1-c6b83b5bd345
Sinning, Irmgard
fbc3f199-8a3b-47a6-9ee7-00bfc472e079
Müller, Sylke
bebf2a17-a17d-4200-a19c-694dc5b086a6
Macheroux, Peter
e1c49266-c971-42f7-86ae-394bd128d040
Tews, Ivo
9117fc5e-d01c-4f8d-a734-5b14d3eee8dd
Kappes, Barbara
10edf779-dc81-4973-878b-d3177273f86a

Gengenbacher, Martin, Fitzpatrick, Teresa B, Raschle, Thomas, Flicker, Karlheinz, Sinning, Irmgard, Müller, Sylke, Macheroux, Peter, Tews, Ivo and Kappes, Barbara (2006) Vitamin B6 biosynthesis by the malaria parasite Plasmodium falciparum: biochemical and structural insights. The Journal of Biological Chemistry, 281 (6), 3633-3641. (doi:10.1074/jbc.M508696200). (PMID:16339145)

Record type: Article

Abstract

Vitamin B6 is one of nature's most versatile cofactors. Most organisms synthesize vitamin B6 via a recently discovered pathway employing the proteins Pdx1 and Pdx2. Here we present an in-depth characterization of the respective orthologs from the malaria parasite, Plasmodium falciparum. Expression profiling of Pdx1 and -2 shows that blood-stage parasites indeed possess a functional vitamin B6 de novo biosynthesis. Recombinant Pdx1 and Pdx2 form a complex that functions as a glutamine amidotransferase with Pdx2 as the glutaminase and Pdx1 as pyridoxal-5 '-phosphate synthase domain. Complex formation is required for catalytic activity of either domain. Pdx1 forms a chimeric bi-enzyme with the bacterial YaaE, a Pdx2 ortholog, both in vivo and in vitro, although this chimera does not attain full catalytic activity, emphasizing that species-specific structural features govern the interaction between the protein partners of the PLP synthase complexes in different organisms. To gain insight into the activation mechanism of the parasite bi-enzyme complex, the three-dimensional structure of Pdx2 was determined at 1.62 A. The obstruction of the oxyanion hole indicates that Pdx2 is in a resting state and that activation occurs upon Pdx1-Pdx2 complex formation.

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Published date: 10 February 2006
Organisations: Centre for Biological Sciences

Identifiers

Local EPrints ID: 200637
URI: http://eprints.soton.ac.uk/id/eprint/200637
ISSN: 0021-9258
PURE UUID: 475da37d-9e2f-432f-aab2-b5962615b7d7
ORCID for Ivo Tews: ORCID iD orcid.org/0000-0002-4704-1139

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Date deposited: 01 Nov 2011 15:13
Last modified: 15 Mar 2024 03:36

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Contributors

Author: Martin Gengenbacher
Author: Teresa B Fitzpatrick
Author: Thomas Raschle
Author: Karlheinz Flicker
Author: Irmgard Sinning
Author: Sylke Müller
Author: Peter Macheroux
Author: Ivo Tews ORCID iD
Author: Barbara Kappes

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