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Title: Structures of the Mycobacterium tuberculosis GlpX protein (class II fructose-1,6-bisphosphatase): Implications for the active oligomeric state, catalytic mechanism and citrate inhibition

Abstract

The crystal structures of native class II fructose-1,6-bisphosphatase (FBPaseII) from Mycobacterium tuberculosis at 2.6 Å resolution and two active-site protein variants are presented. The variants were complexed with the reaction product fructose 6-phosphate (F6P). The Thr84Ala mutant is inactive, while the Thr84Ser mutant has a lower catalytic activity. The structures reveal the presence of a 222 tetramer, similar to those described for fructose-1,6/sedoheptulose-1,7-bisphosphatase from Synechocystis(strain 6803) as well as the equivalent enzyme from Thermosynechococcus elongatus. This homotetramer corresponds to a homologous oligomer that is present but not described in the crystal structure of FBPaseII from Escherichia coli and is probably conserved in all FBPaseIIs. The constellation of amino-acid residues in the active site of FBPaseII from M. tuberculosis ( MtFBPaseII) is conserved and is analogous to that described previously for the E. coli enzyme. Moreover, the structure of the active site of the partially active (Thr84Ser) variant and the analysis of the kinetics are consistent with the previously proposed catalytic mechanism. The presence of metabolites in the crystallization medium (for example citrate and malonate) and in the corresponding crystal structures of MtFBPaseII, combined with their observed inhibitory effect, could suggest the existence of an uncharacterized inhibition of this class ofmore » enzymes besides the allosteric inhibition by adenosine monophosphate observed for the Synechocystis enzyme. The structural and functional insights derived from the structure of MtFBPaseII will provide critical information for the design of lead inhibitors, which will be used to validate this target for future chemical intervention.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
OTHER
OSTI Identifier:
1499761
Resource Type:
Journal Article
Journal Name:
Acta Crystallographica. Section D. Structural Biology
Additional Journal Information:
Journal Volume: 74; Journal Issue: 4; Journal ID: ISSN 2059-7983
Publisher:
IUCr
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Wolf, Nina M., Gutka, Hiten J., Movahedzadeh, Farahnaz, and Abad-Zapatero, Celerino. Structures of the Mycobacterium tuberculosis GlpX protein (class II fructose-1,6-bisphosphatase): Implications for the active oligomeric state, catalytic mechanism and citrate inhibition. United States: N. p., 2018. Web. doi:10.1107/S2059798318002838.
Wolf, Nina M., Gutka, Hiten J., Movahedzadeh, Farahnaz, & Abad-Zapatero, Celerino. Structures of the Mycobacterium tuberculosis GlpX protein (class II fructose-1,6-bisphosphatase): Implications for the active oligomeric state, catalytic mechanism and citrate inhibition. United States. doi:10.1107/S2059798318002838.
Wolf, Nina M., Gutka, Hiten J., Movahedzadeh, Farahnaz, and Abad-Zapatero, Celerino. Sun . "Structures of the Mycobacterium tuberculosis GlpX protein (class II fructose-1,6-bisphosphatase): Implications for the active oligomeric state, catalytic mechanism and citrate inhibition". United States. doi:10.1107/S2059798318002838.
@article{osti_1499761,
title = {Structures of the Mycobacterium tuberculosis GlpX protein (class II fructose-1,6-bisphosphatase): Implications for the active oligomeric state, catalytic mechanism and citrate inhibition},
author = {Wolf, Nina M. and Gutka, Hiten J. and Movahedzadeh, Farahnaz and Abad-Zapatero, Celerino},
abstractNote = {The crystal structures of native class II fructose-1,6-bisphosphatase (FBPaseII) from Mycobacterium tuberculosis at 2.6 Å resolution and two active-site protein variants are presented. The variants were complexed with the reaction product fructose 6-phosphate (F6P). The Thr84Ala mutant is inactive, while the Thr84Ser mutant has a lower catalytic activity. The structures reveal the presence of a 222 tetramer, similar to those described for fructose-1,6/sedoheptulose-1,7-bisphosphatase fromSynechocystis(strain 6803) as well as the equivalent enzyme from Thermosynechococcus elongatus. This homotetramer corresponds to a homologous oligomer that is present but not described in the crystal structure of FBPaseII from Escherichia coli and is probably conserved in all FBPaseIIs. The constellation of amino-acid residues in the active site of FBPaseII from M. tuberculosis (MtFBPaseII) is conserved and is analogous to that described previously for the E. coli enzyme. Moreover, the structure of the active site of the partially active (Thr84Ser) variant and the analysis of the kinetics are consistent with the previously proposed catalytic mechanism. The presence of metabolites in the crystallization medium (for example citrate and malonate) and in the corresponding crystal structures of MtFBPaseII, combined with their observed inhibitory effect, could suggest the existence of an uncharacterized inhibition of this class of enzymes besides the allosteric inhibition by adenosine monophosphate observed for the Synechocystis enzyme. The structural and functional insights derived from the structure of MtFBPaseII will provide critical information for the design of lead inhibitors, which will be used to validate this target for future chemical intervention.},
doi = {10.1107/S2059798318002838},
journal = {Acta Crystallographica. Section D. Structural Biology},
issn = {2059-7983},
number = 4,
volume = 74,
place = {United States},
year = {2018},
month = {4}
}