scholarly journals Altering the allosteric pathway in IGPS suppresses millisecond motions and catalytic activity

2017 ◽  
Vol 114 (17) ◽  
pp. E3414-E3423 ◽  
Author(s):  
George P. Lisi ◽  
Kyle W. East ◽  
Victor S. Batista ◽  
J. Patrick Loria
Keyword(s):  
Enzyme Inhibitors ◽  
Therapeutic Benefit ◽  
Relaxation Dispersion ◽  
Multiple Quantum ◽  
Glycerol Phosphate ◽  
Allosteric Enzyme ◽  
Kinetic Activity ◽  
Allosteric Sites ◽  
Imidazole Glycerol Phosphate ◽  
Functional Relevance

Imidazole glycerol phosphate synthase (IGPS) is a V-type allosteric enzyme, meaning that its catalytic rate is critically dependent on activation by its allosteric ligand, N′-[(5′-phosphoribulosyl)formimino]-5-aminoimidazole-4-carboxamide ribonucleotide (PRFAR). The allosteric mechanism of IGPS is reliant on millisecond conformational motions for efficient catalysis. We engineered four mutants of IGPS designed to disrupt millisecond motions and allosteric coupling to identify regions that are critical to IGPS function. Multiple-quantum Carr–Purcell–Meiboom–Gill (CPMG) relaxation dispersion experiments and NMR chemical shift titrations reveal diminished enzyme flexibility and a reshaping of the allosteric connectivity in each mutant construct, respectively. The functional relevance of the observed motional quenching is confirmed by significant reductions in glutaminase kinetic activity and allosteric ligand binding affinity. This work presents relevant conclusions toward the control of protein allostery and design of unique allosteric sites for potential enzyme inhibitors with regulatory or therapeutic benefit.

scholarly journals Eigenvector centrality for characterization of protein allosteric pathways

2018 ◽  
Vol 115 (52) ◽  
pp. E12201-E12208 ◽  
Author(s):  
Christian F. A. Negre ◽  
Uriel N. Morzan ◽  
Heidi P. Hendrickson ◽  
Rhitankar Pal ◽  
George P. Lisi ◽  
...  
Keyword(s):  
Cost Effective ◽  
Site Directed Mutagenesis ◽  
Amino Acid Residues ◽  
Eigenvector Centrality ◽  
Glycerol Phosphate ◽  
Allosteric Enzyme ◽  
Characterization Methods ◽  
Intrinsic Complexity ◽  
Imidazole Glycerol Phosphate ◽  
Allosteric Mechanisms

Determining the principal energy-transfer pathways responsible for allosteric communication in biomolecules remains challenging, partially due to the intrinsic complexity of the systems and the lack of effective characterization methods. In this work, we introduce the eigenvector centrality metric based on mutual information to elucidate allosteric mechanisms that regulate enzymatic activity. Moreover, we propose a strategy to characterize the range of correlations that underlie the allosteric processes. We use the V-type allosteric enzyme imidazole glycerol phosphate synthase (IGPS) to test the proposed methodology. The eigenvector centrality method identifies key amino acid residues of IGPS with high susceptibility to effector binding. The findings are validated by solution NMR measurements yielding important biological insights, including direct experimental evidence for interdomain motion, the central role played by helix hα1, and the short-range nature of correlations responsible for the allosteric mechanism. Beyond insights on IGPS allosteric pathways and the nature of residues that could be targeted by therapeutic drugs or site-directed mutagenesis, the reported findings demonstrate the eigenvector centrality analysis as a general cost-effective methodology to gain fundamental understanding of allosteric mechanisms at the molecular level.

ChemInform Abstract: Synthesis of Inhibitors of Imidazole Glycerol Phosphate Dehydratase.

ChemInform ◽  
2010 ◽  
Vol 27 (28) ◽  
pp. no-no
Author(s):  
S. D. LINDELL ◽  
C. G. EARNSHAW ◽  
B. J. WRIGHT ◽  
D. S. CARVER ◽  
M. J. O'MAHONY ◽  
...  
Keyword(s):  
Glycerol Phosphate ◽  
Imidazole Glycerol Phosphate

scholarly journals In vivo evaluation of the interaction between the Escherichia coli IGP synthase subunits using the Bacterial Two-Hybrid system

2020 ◽  
Vol 367 (14) ◽  
Author(s):  
Sofia Chioccioli ◽  
Patrizia Bogani ◽  
Sara Del Duca ◽  
Lara Mitia Castronovo ◽  
Alberto Vassallo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Hybrid System ◽  
De Novo ◽  
Glycerol Phosphate ◽  
In Vivo Evaluation ◽  
Igp Synthase ◽  
Imidazole Glycerol Phosphate ◽  
Two Hybrid

ABSTRACT Histidine biosynthesis is one of the most characterized metabolic routes for its antiquity and its central role in cellular metabolism; indeed, it represents a cross-road between nitrogen metabolism and de novo synthesis of purines. This interconnection is due to the activity of imidazole glycerol phosphate synthase, a heterodimeric enzyme constituted by the products of two his genes, hisH and hisF, encoding a glutamine amidotransferase and a cyclase, respectively. Despite their interaction was suggested by several in vitro experiments, their in vivo complex formation has not been demonstrated. On the contrary, the analysis of the entire Escherichia coli interactome performed using the yeast two hybrid system did not suggest the in vivo interaction of the two IGP synthase subunits. The aim of this study was to demonstrate the interaction of the two proteins using the Bacterial Adenylate Cyclase Two-Hybrid (BACTH) system. Data obtained demonstrated the in vivo interaction occurring between the proteins encoded by the E. coli hisH and hisF genes; this finding might also open the way to pharmaceutical applications through the design of selective drugs toward this enzyme.

Discovery of imidazole glycerol phosphate dehydratase inhibitors through 3-D database searching

2002 ◽  
Vol 12 (13) ◽  
pp. 1743-1746 ◽  
Author(s):  
Barbara A Schweitzer ◽  
Paul J Loida ◽  
Claire A CaJacob ◽  
Robert C Chott ◽  
Elizabeth M Collantes ◽  
...  
Keyword(s):  
Database Searching ◽  
Glycerol Phosphate ◽  
Imidazole Glycerol Phosphate

The O-Linked N-Acetylglucosamine Transferase Modifies HOXA9 and Inhibits HOXA9-Driven Immortalization

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4901-4901
Author(s):  
Jean-Francois M Rual ◽  
Jay L. Hess ◽  
Tao Xu ◽  
Cailin Collins ◽  
Honglai Zhang ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Bone Marrow Cells ◽  
Conflicts Of Interest ◽  
Therapeutic Benefit ◽  
Core Element ◽  
Hematopoietic Stem ◽  
Primary Bone ◽  
Functional Relevance ◽  
Primary Bone Marrow

Abstract The homeodomain-containing transcription factor HOXA9 is a core element of the HOXA9 enhanceosome, a critical DNA-protein complex that regulates hematopoietic stem cell self-renewal during hematopoiesis. Several genetic mutations observed in acute myeloid leukemia (AML) patients, including MLL translocations, are associated with aberrant up regulation of HOXA9, thus disrupting the hematopoietic balance towards leukemogenesis. While analyses of HOXA9 and cofactors have uncovered fundamental aspects of the mechanisms through which these proteins mediate their functions, questions remain. For example, what molecular mechanisms contribute to switching HOXA9 enhanceosomes off during myeloid differentiation? Could these mechanisms be targeted for the therapeutic benefit of leukemia patients? Characterization of the molecular interactions in which HOXA9 enhanceosome proteins are involved should shed light on the mechanisms that govern these proteins during both normal hematopoiesis and leukemogenesis. We recently discovered that HOXA9 interacts physically with OGT, the only O-linked N-acetyl glucosamine transferase in humans. We also demonstrated that HOXA9 is O-GlcNAcylated by OGT. Investigation of the functional relevance of this interaction to HOXA9-driven leukemogenesis is currently under way using interaction- and O-GlcNAcylation-deficient alleles of HOXA9 in a colony formation assay. Our preliminary results suggest that OGT inhibits HOXA9’s ability to transform primary bone marrow cells, thus suggesting OGT is a potential tumor suppressor of HOXA9-driven leukemogenesis. Current efforts focus on further dissecting the molecular interplay occurring between HOXA9 and OGT on chromatin, its impact on the regulation of HOXA9 targets and its role in HOXA9-driven leukemogenesis. Work is also under way to identify factors involved in the OGT-mediated regulation of HOXA9 enhanceosomes. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Crystal Structure of Imidazole Glycerol Phosphate Synthase

Structure ◽  
2001 ◽  
Vol 9 (10) ◽  
pp. 987-997 ◽  
Author(s):  
Barnali N Chaudhuri ◽  
Stephanie C Lange ◽  
Rebecca S Myers ◽  
Sridar V Chittur ◽  
V.Jo Davisson ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Glycerol Phosphate ◽  
Imidazole Glycerol Phosphate ◽  
Phosphate Synthase

scholarly journals Crystal Structure of Imidazole Glycerol-phosphate Dehydratase

2004 ◽  
Vol 279 (15) ◽  
pp. 15491-15498 ◽  
Author(s):  
Sangita C. Sinha ◽  
Barnali N. Chaudhuri ◽  
John W. Burgner ◽  
Galina Yakovleva ◽  
V. Jo Davisson ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Glycerol Phosphate ◽  
Imidazole Glycerol Phosphate
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