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Evidence for dimer/tetramer equilibrium in Trypanosoma brucei 6-phosphogluconate dehydrogenase.
Biochim Biophys Acta. 2013 Dec; 1834(12):2647-52.BB

Abstract

6-Phosphogluconate dehydrogenase (6PGDH), the third enzyme of the pentose phosphate pathway (PPP), is essential for biosyntheses and oxidative stress defence. It also has the function of depleting 6PG, whose accumulation induces cell senescence. 6PGDH is a proposed drug target for African trypanosomiasis caused by Trypanosoma brucei and for other microbial infections and cancer. Gel filtration, density gradient sedimentation, cross-linking and dynamic light scattering were used to assay the oligomerization state of T. brucei 6PGDH in the absence and presence of several ligands. The enzyme displays a dimer-tetramer equilibrium and NADPH (but not NADP) reduces the rate of approach to equilibrium, while 6PG is able to antagonize the NADPH effect. The different behaviour of the two forms of coenzyme appears to be related to the differences in ΔCp, with NADP binding ΔCp closer to what is expected of crystallographic structures, while NADPH ΔCp is three times larger. The estimated dimer-tetramer association constant is 1.5·10(6)M(-1), and the specific activity of the tetramer is about 3 fold higher than the specific activity of the dimer. Thus, cellular conditions promoting tetramer formation could allow an efficient clearing of 6PG. Experiments carried out on sheep liver 6PGDH indicate that tetramerization is a specificity of the parasite enzyme.

Authors+Show Affiliations

Dept. of Biomedical and Specialty Surgical Sciences, Biochemistry Unit, Via Borsari 46, Università di Ferrara, 44121 Ferrara, Italy. Electronic address: hns@unife.it.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

24096100

Citation

Hanau, S, et al. "Evidence for Dimer/tetramer Equilibrium in Trypanosoma Brucei 6-phosphogluconate Dehydrogenase." Biochimica Et Biophysica Acta, vol. 1834, no. 12, 2013, pp. 2647-52.
Hanau S, d'Empaire LP, Capone I, et al. Evidence for dimer/tetramer equilibrium in Trypanosoma brucei 6-phosphogluconate dehydrogenase. Biochim Biophys Acta. 2013;1834(12):2647-52.
Hanau, S., d'Empaire, L. P., Capone, I., Alberighi, S., Montioli, R., & Dallocchio, F. (2013). Evidence for dimer/tetramer equilibrium in Trypanosoma brucei 6-phosphogluconate dehydrogenase. Biochimica Et Biophysica Acta, 1834(12), 2647-52. https://doi.org/10.1016/j.bbapap.2013.09.018
Hanau S, et al. Evidence for Dimer/tetramer Equilibrium in Trypanosoma Brucei 6-phosphogluconate Dehydrogenase. Biochim Biophys Acta. 2013;1834(12):2647-52. PubMed PMID: 24096100.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Evidence for dimer/tetramer equilibrium in Trypanosoma brucei 6-phosphogluconate dehydrogenase. AU - Hanau,S, AU - d'Empaire,L Proietti, AU - Capone,I, AU - Alberighi,S, AU - Montioli,R, AU - Dallocchio,F, Y1 - 2013/10/02/ PY - 2013/07/16/received PY - 2013/09/13/revised PY - 2013/09/25/accepted PY - 2013/10/8/entrez PY - 2013/10/8/pubmed PY - 2014/2/22/medline KW - 4-phospho-erythronate KW - 4PE KW - 6-phosphogluconate KW - 6-phosphogluconate dehydrogenase KW - 6PG KW - 6PGDH KW - ASA(ap) KW - ASA(p) KW - DLS KW - Dimer–tetramer equilibrium KW - G6PDH KW - ITC KW - NADPH inhibition KW - PPP KW - Pentose phosphate pathway KW - Trypanosoma brucei KW - apolar solvent-accessible surface area KW - dynamic light scattering KW - glucose-6-phosphate dehydrogenase KW - isothermal titration calorimetry KW - pentose phosphate pathway KW - polar solvent-accessible surface area SP - 2647 EP - 52 JF - Biochimica et biophysica acta JO - Biochim. Biophys. Acta VL - 1834 IS - 12 N2 - 6-Phosphogluconate dehydrogenase (6PGDH), the third enzyme of the pentose phosphate pathway (PPP), is essential for biosyntheses and oxidative stress defence. It also has the function of depleting 6PG, whose accumulation induces cell senescence. 6PGDH is a proposed drug target for African trypanosomiasis caused by Trypanosoma brucei and for other microbial infections and cancer. Gel filtration, density gradient sedimentation, cross-linking and dynamic light scattering were used to assay the oligomerization state of T. brucei 6PGDH in the absence and presence of several ligands. The enzyme displays a dimer-tetramer equilibrium and NADPH (but not NADP) reduces the rate of approach to equilibrium, while 6PG is able to antagonize the NADPH effect. The different behaviour of the two forms of coenzyme appears to be related to the differences in ΔCp, with NADP binding ΔCp closer to what is expected of crystallographic structures, while NADPH ΔCp is three times larger. The estimated dimer-tetramer association constant is 1.5·10(6)M(-1), and the specific activity of the tetramer is about 3 fold higher than the specific activity of the dimer. Thus, cellular conditions promoting tetramer formation could allow an efficient clearing of 6PG. Experiments carried out on sheep liver 6PGDH indicate that tetramerization is a specificity of the parasite enzyme. SN - 0006-3002 UR - https://www.unboundmedicine.com/medline/citation/24096100/Evidence_for_dimer/tetramer_equilibrium_in_Trypanosoma_brucei_6_phosphogluconate_dehydrogenase_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1570-9639(13)00352-X DB - PRIME DP - Unbound Medicine ER -