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Wu B, Liang Z, Lan H, Teng X, Wang C. The role of PKM2 in cancer progression and its structural and biological basis. J Physiol Biochem 2024; 80:261-275. [PMID: 38329688 DOI: 10.1007/s13105-024-01007-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 01/10/2024] [Indexed: 02/09/2024]
Abstract
Pyruvate kinase M2 (PKM2), a subtype of pyruvate kinase (PK), has been shown to play an important role in the development of cancer. It regulates the last step of glycolytic pathway. PKM2 has both pyruvate kinase and protein kinase activity, and the conversion of these two functions of PKM2 depends on the mutual change of dimer and tetramer. The dimerization of PKM2 can promote the proliferation and growth of tumor cells, so inhibiting the dimerization of PKM2 is essential to curing cancer. The aggregation of PKM2 is regulated by both endogenous and exogenous cofactors as well as post-translational modification (PTM). Although there are many studies on the different aggregation of PKM2 in the process of tumor development, there are few summaries in recent years. In this review, we first introduce the role of PKM2 in various biological processes of tumor growth. Then, we summarize the aggregation regulation mechanism of PKM2 by various endogenous cofactors such as Fructose-1, 6-diphosphate (FBP), various amino acids, and post-translational modification (PTMs). Finally, the related inhibitors and agonists of PKM2 are summarized to provide reference for regulating PKM2 aggregation in the treatment of cancer in the future.
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Affiliation(s)
- Bingxin Wu
- State Key Laboratory of Traditional Chinese Medicine Syndrome, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Zuhui Liang
- State Key Laboratory of Traditional Chinese Medicine Syndrome, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Huan Lan
- State Key Laboratory of Traditional Chinese Medicine Syndrome, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Xiaojun Teng
- State Key Laboratory of Traditional Chinese Medicine Syndrome, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Caiyan Wang
- State Key Laboratory of Traditional Chinese Medicine Syndrome, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China.
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2
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Abeynayake NS, Le N, Sanchez-Lecuona G, Donnadieu B, Webster CE, Montiel-Palma V. Unexpected alkyl isomerization at the silicon ligand of an unsaturated Rh complex: combined experiment and theory. Dalton Trans 2023; 52:16159-16166. [PMID: 37877892 DOI: 10.1039/d3dt02087h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
The formation of dimer [(μ-Cl)Rh-(κ3(P,Si,Si)PhP(o-C6H4CH2SiiPr2)(o-C6H4CH2SiiPrnPr))]2 (Rh-3) with an n-propyl group on one of the silicon atoms as a minor product was affected by the reaction of [RhCl(COD)]2 with proligand PhP(o-C6H4CH2SiHiPr2)2, L1. The major product of the reaction was monomeric 14-electron Rh(III) complex [ClRh(κ3(P,Si,Si)PhP(o-C6H4CH2SiiPr2)2)] (Rh-1). Computations revealed that the monomer-dimer equilibrium is shifted toward the monomer with four isopropyl substituents on the two Si atoms of the ligand as in Rh-1; conversely, the dimer is favored with only one n-propyl as in Rh-3, and with less bulky alkyl substituents such as in [ClRh(κ3(P,Si,Si)PhP(o-C6H4CH2SiMe2)2]2 (Rh-2). Computations on the mechanism of formation of Rh-3 directly from [RhCl(COD)]2 are in agreement with the experimental findings and it is found to be less energetic than if stemming from Rh-1. Additionally, a Si-O-Si complex, [μ-Cl-Rh{κ3(P,Si,C)PPh(o-C6H4CH2SiiPrO SiiPr2CH-o-C6H4)}]2, Rh-4, is generated from the reaction of Rh-1 with adventitious water as a result of intramolecular C-H activation.
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Affiliation(s)
- Niroshani S Abeynayake
- Department of Chemistry, Mississippi State University, Box 9573, Mississippi State, Mississippi 39762, USA.
| | - Nghia Le
- Department of Chemistry, Mississippi State University, Box 9573, Mississippi State, Mississippi 39762, USA.
| | - Gabriela Sanchez-Lecuona
- Department of Chemistry, Mississippi State University, Box 9573, Mississippi State, Mississippi 39762, USA.
| | - Bruno Donnadieu
- Department of Chemistry, Mississippi State University, Box 9573, Mississippi State, Mississippi 39762, USA.
| | - Charles Edwin Webster
- Department of Chemistry, Mississippi State University, Box 9573, Mississippi State, Mississippi 39762, USA.
| | - Virginia Montiel-Palma
- Department of Chemistry, Mississippi State University, Box 9573, Mississippi State, Mississippi 39762, USA.
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Dimitrijevs P, Makrecka-Kuka M, Bogucka A, Hyvönen M, Pantelejevs T, Arsenyan P. Development of isoselenazolium chlorides as selective pyruvate kinase isoform M2 inhibitors. Eur J Med Chem 2023; 257:115504. [PMID: 37216812 DOI: 10.1016/j.ejmech.2023.115504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 05/12/2023] [Accepted: 05/16/2023] [Indexed: 05/24/2023]
Abstract
Alterations in cancer metabolic pathways open up an opportunity for targeted and effective elimination of tumor cells. Pyruvate kinase M2 (PKM2) is predominantly expressed in proliferating cells and plays an essential role in directing glucose metabolism in cancer. Here, we report the design of novel class of selective PKM2 inhibitors as anti-cancer agents and their mechanism of action. Compound 5c being the most active with IC50 = 0.35 ± 0.07 μM, also downregulates PKM2 mRNA expression, modulates mitochondrial functionality, induces oxidative burst and is cytotoxic for various cancer types. Isoselenazolium chlorides have an unusual mechanism of PKM2 inhibition, inducing a functionally deficient tetrameric assembly, while exhibiting a competitive inhibitor character. The discovery of robust PKM2 inhibitors not only offers candidates for anticancer therapy but is also crucial for studying the role of PKM2 in cancer.
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Affiliation(s)
- Pavels Dimitrijevs
- Latvian Institute of Organic Synthesis, Aizkraukles 21, LV1006, Riga, Latvia
| | | | - Agnieszka Bogucka
- Department of Biochemistry, University of Cambridge, Sanger Building, 80 Tennis Ct Rd, Cambridge, CB2 1GA, UK
| | - Marko Hyvönen
- Department of Biochemistry, University of Cambridge, Sanger Building, 80 Tennis Ct Rd, Cambridge, CB2 1GA, UK
| | - Teodors Pantelejevs
- Latvian Institute of Organic Synthesis, Aizkraukles 21, LV1006, Riga, Latvia
| | - Pavel Arsenyan
- Latvian Institute of Organic Synthesis, Aizkraukles 21, LV1006, Riga, Latvia.
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Swint-Kruse L, Dougherty LL, Page B, Wu T, O’Neil PT, Prasannan CB, Timmons C, Tang Q, Parente DJ, Sreenivasan S, Holyoak T, Fenton AW. PYK-SubstitutionOME: an integrated database containing allosteric coupling, ligand affinity and mutational, structural, pathological, bioinformatic and computational information about pyruvate kinase isozymes. Database (Oxford) 2023; 2023:baad030. [PMID: 37171062 PMCID: PMC10176505 DOI: 10.1093/database/baad030] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 03/29/2023] [Accepted: 04/11/2023] [Indexed: 05/13/2023]
Abstract
Interpreting changes in patient genomes, understanding how viruses evolve and engineering novel protein function all depend on accurately predicting the functional outcomes that arise from amino acid substitutions. To that end, the development of first-generation prediction algorithms was guided by historic experimental datasets. However, these datasets were heavily biased toward substitutions at positions that have not changed much throughout evolution (i.e. conserved). Although newer datasets include substitutions at positions that span a range of evolutionary conservation scores, these data are largely derived from assays that agglomerate multiple aspects of function. To facilitate predictions from the foundational chemical properties of proteins, large substitution databases with biochemical characterizations of function are needed. We report here a database derived from mutational, biochemical, bioinformatic, structural, pathological and computational studies of a highly studied protein family-pyruvate kinase (PYK). A centerpiece of this database is the biochemical characterization-including quantitative evaluation of allosteric regulation-of the changes that accompany substitutions at positions that sample the full conservation range observed in the PYK family. We have used these data to facilitate critical advances in the foundational studies of allosteric regulation and protein evolution and as rigorous benchmarks for testing protein predictions. We trust that the collected dataset will be useful for the broader scientific community in the further development of prediction algorithms. Database URL https://github.com/djparente/PYK-DB.
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Affiliation(s)
- Liskin Swint-Kruse
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160, USA
| | - Larissa L Dougherty
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160, USA
| | - Braelyn Page
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160, USA
| | - Tiffany Wu
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160, USA
| | - Pierce T O’Neil
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160, USA
| | - Charulata B Prasannan
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160, USA
| | - Cody Timmons
- Chemistry Department, Southwestern Oklahoma State University, 100 Campus Dr., Weatherford, OK 73096, USA
| | - Qingling Tang
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160, USA
| | - Daniel J Parente
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160, USA
- Department of Family Medicine and Community Health, The University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160, USA
| | - Shwetha Sreenivasan
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160, USA
| | - Todd Holyoak
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160, USA
- Department of Biology, University of Waterloo, 200 University Ave. W, Waterloo, ON N2L 3G1, Canada
| | - Aron W Fenton
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160, USA
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Nandi S, Dey M. Identification of residues involved in allosteric signal transmission from amino acid binding site of pyruvate kinase muscle isoform 2. PLoS One 2023; 18:e0282508. [PMID: 36897854 PMCID: PMC10004559 DOI: 10.1371/journal.pone.0282508] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 02/16/2023] [Indexed: 03/11/2023] Open
Abstract
PKM2 is a rate-limiting enzyme in the glycolytic process and is involved in regulating tumor proliferation. Several amino acids (AAs) such as Asn, Asp, Val, and Cys have been shown to bind to the AA binding pocket of PKM2 and modulate its oligomeric state, substrate binding affinity, and activity. Although previous studies have attributed that the main chain and side chain of bound AAs are responsible for initiating signal to regulate PKM2, the signal transduction pathway remains elusive. To identify the residues involved in signal transfer process, N70 and N75 located at two ends of a β strand connecting the active site and AA binding pocket were altered. Biochemical studies of these variants with various AA ligands (Asn, Asp, Val, and Cys), illustrate that N70 and N75, along with β1 connecting these residues are part of the signal transduction pathway between the AA binding pocket and the active site. The results demonstrate that mutation of N70 to D prevents the transfer of the inhibitory signal mediated by Val and Cys, whereas N75 to L alteration blocks the activating signal initiated by Asn and Asp. Taken together, this study confirms that N70 is one of the residues responsible for transmitting the inhibitory signal and N75 is involved in the activation signal flow.
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Affiliation(s)
- Suparno Nandi
- Department of Chemistry, The University of Iowa, Iowa City, IA, United States of America
| | - Mishtu Dey
- Department of Chemistry, The University of Iowa, Iowa City, IA, United States of America
- * E-mail: ,
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Zeng X, Li X, Li C. Seasons affect the phosphorylation of pork sarcoplasmic proteins related to meat quality. Anim Biosci 2021; 35:96-104. [PMID: 34474534 PMCID: PMC8738932 DOI: 10.5713/ab.21.0185] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 07/21/2021] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE Sarcoplasmic proteins include proteins that play critical roles in biological processes of living organisms. How seasons influence biological processes and meat quality of postmortem muscles through the regulation of protein phosphorylation remain to be investigated. In this study, the phosphorylation of sarcoplasmic proteins in pork longissimus muscle was investigated in four seasons. METHODS Sarcoplasmic proteins were extracted from 40 pork carcasses (10 for each season) and analyzed through ProQ Diamond staining for phosphorylation labeling and Sypro Ruby staining for total protein labeling. The pH of muscle, contents of glycogen and ATP were measured at 45 min, 3 h, and 9 h postmortem and the water (P2b, P21, and P22) was measured at 3 h and 9 h. RESULTS A total of 21 bands were detected. Band 8 (heat shock cognate 71 kDa protein; heat shock 70 kDa protein 1B) had higher phosphorylation level in summer than that in other seasons at 45 min postmortem. The phosphorylation levels of 3 Bands were significantly different between fast and normal pH decline groups (p<0.05). The phosphorylation levels of 4 bands showed negative associations with immobilized water (P21) and positive association with free water (P22). CONCLUSION The phosphorylation levels of sarcoplasmic proteins involved in energy metabolism and heat stress response at early postmortem time differed depending on the seasons. These proteins include heat shock protein 70, pyruvate kinase, phosphoglucomutase-1, glucose-6-phosphate isomerase, and carbonic anhydrase 3. High temperatures in summer might result in the phosphorylation of those proteins, leading to pH decline and low water holding capacity.
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Affiliation(s)
- Xianming Zeng
- Key Laboratory of Meat Processing and Quality Control, MOE, Nanjing, 210095, China.,Key Laboratory of Animal Products Processing, MOA, Nanjing, 210095, China.,Jiangsu Synergetic Innovation Center of Meat Production, Processing and Quality Control, Nanjing, 210095, China.,College of Food Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xiao Li
- Key Laboratory of Meat Processing and Quality Control, MOE, Nanjing, 210095, China.,Key Laboratory of Animal Products Processing, MOA, Nanjing, 210095, China.,Jiangsu Synergetic Innovation Center of Meat Production, Processing and Quality Control, Nanjing, 210095, China.,College of Food Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Chunbao Li
- Key Laboratory of Meat Processing and Quality Control, MOE, Nanjing, 210095, China.,Key Laboratory of Animal Products Processing, MOA, Nanjing, 210095, China.,Jiangsu Synergetic Innovation Center of Meat Production, Processing and Quality Control, Nanjing, 210095, China.,College of Food Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
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Rathod B, Chak S, Patel S, Shard A. Tumor pyruvate kinase M2 modulators: a comprehensive account of activators and inhibitors as anticancer agents. RSC Med Chem 2021; 12:1121-1141. [PMID: 34355179 PMCID: PMC8292966 DOI: 10.1039/d1md00045d] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 03/25/2021] [Indexed: 12/16/2022] Open
Abstract
Pyruvate kinase M2 (PKM2) catalyzes the conversion of phosphoenolpyruvate (PEP) to pyruvate. It plays a central role in the metabolic reprogramming of cancer cells and is expressed in most human tumors. It is essential in indiscriminate proliferation, survival, and tackling apoptosis in cancer cells. This positions PKM2 as a hot target in cancer therapy. Despite its well-known structure and several reported modulators targeting PKM2 as activators or inhibitors, a comprehensive review focusing on such modulators is lacking. Herein we summarize modulators of PKM2, the assays used to detect their potential, the preferable tense (T) and relaxed (R) states in which the enzyme resides, lacunae in existing modulators, and several strategies that may lead to effective anticancer drug development targeting PKM2.
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Affiliation(s)
- Bhagyashri Rathod
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research Ahmedabad Opposite Air Force Station Gandhinagar Gujarat 382355 India
| | - Shivam Chak
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research Ahmedabad Opposite Air Force Station Gandhinagar Gujarat 382355 India
| | - Sagarkumar Patel
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research Ahmedabad Opposite Air Force Station Gandhinagar Gujarat 382355 India
| | - Amit Shard
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research Ahmedabad Opposite Air Force Station Gandhinagar Gujarat 382355 India
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Nandi S, Razzaghi M, Srivastava D, Dey M. Structural basis for allosteric regulation of pyruvate kinase M2 by phosphorylation and acetylation. J Biol Chem 2021; 295:17425-17440. [PMID: 33453989 DOI: 10.1074/jbc.ra120.015800] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/18/2020] [Indexed: 01/01/2023] Open
Abstract
Pyruvate kinase muscle isoform 2 (PKM2) is a key glycolytic enzyme and transcriptional coactivator and is critical for tumor metabolism. In cancer cells, native tetrameric PKM2 is phosphorylated or acetylated, which initiates a switch to a dimeric/monomeric form that translocates into the nucleus, causing oncogene transcription. However, it is not known how these post-translational modifications (PTMs) disrupt the oligomeric state of PKM2. We explored this question via crystallographic and biophysical analyses of PKM2 mutants containing residues that mimic phosphorylation and acetylation. We find that the PTMs elicit major structural reorganization of the fructose 1,6-bisphosphate (FBP), an allosteric activator, binding site, impacting the interaction with FBP and causing a disruption in oligomerization. To gain insight into how these modifications might cause unique outcomes in cancer cells, we examined the impact of increasing the intracellular pH (pHi) from ∼7.1 (in normal cells) to ∼7.5 (in cancer cells). Biochemical studies of WT PKM2 (wtPKM2) and the two mimetic variants demonstrated that the activity decreases as the pH is increased from 7.0 to 8.0, and wtPKM2 is optimally active and amenable to FBP-mediated allosteric regulation at pHi 7.5. However, the PTM mimetics exist as a mixture of tetramer and dimer, indicating that physiologically dimeric fraction is important and might be necessary for the modified PKM2 to translocate into the nucleus. Thus, our findings provide insight into how PTMs and pH regulate PKM2 and offer a broader understanding of its intricate allosteric regulation mechanism by phosphorylation or acetylation.
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Affiliation(s)
- Suparno Nandi
- Department of Chemistry, University of Iowa, Iowa City, Iowa, USA
| | | | | | - Mishtu Dey
- Department of Chemistry, University of Iowa, Iowa City, Iowa, USA.
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Functional interplay among thiol-based redox signaling, metabolism, and ferroptosis unveiled by a genetic variant of TP53. Proc Natl Acad Sci U S A 2020; 117:26804-26811. [PMID: 33055209 DOI: 10.1073/pnas.2009943117] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The p53 tumor suppressor protein is a transcription factor and master stress response mediator, and it is subject to reduction-oxidation (redox)-dependent regulation. The P47S variant of TP53, which exists primarily in African-descent populations, associates with an elevated abundance of low molecular weight (LMW) thiols, including glutathione (GSH) and coenzyme A (CoA). Here we show that S47 and P47 cells exhibit distinct metabolic profiles, controlled by their different redox states and expression of Activating Transcription Factor-4 (ATF4). We find that S47 cells exhibit decreased catabolic glycolysis but increased use of the pentose phosphate pathway (PPP), and an enhanced abundance of the antioxidant, NADPH. We identify ATF4 as differentially expressed in P47 and S47 cells and show that ATF4 can reverse the redox status and rescue metabolism of S47 cells, as well as increase sensitivity to ferroptosis. This adaptive metabolic switch is rapid, reversible, and accompanied by thiol-mediated changes in the structures and activities of key glycolytic signaling pathway proteins, including GAPDH and G6PD. The results presented here unveil the important functional interplay among pathways regulating thiol-redox status, metabolic adaptation, and cellular responses to oxidative stress.
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Nandi S, Dey M. Biochemical and structural insights into how amino acids regulate pyruvate kinase muscle isoform 2. J Biol Chem 2020; 295:5390-5403. [PMID: 32144209 PMCID: PMC7170521 DOI: 10.1074/jbc.ra120.013030] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/03/2020] [Indexed: 12/12/2022] Open
Abstract
Pyruvate kinase muscle isoform 2 (PKM2) is a key glycolytic enzyme involved in ATP generation and critical for cancer metabolism. PKM2 is expressed in many human cancers and is regulated by complex mechanisms that promote tumor growth and proliferation. Therefore, it is considered an attractive therapeutic target for modulating tumor metabolism. Various stimuli allosterically regulate PKM2 by cycling it between highly active and less active states. Several small molecules activate PKM2 by binding to its intersubunit interface. Serine and cysteine serve as an activator and inhibitor of PKM2, respectively, by binding to its amino acid (AA)-binding pocket, which therefore represents a potential druggable site. Despite binding similarly to PKM2, how cysteine and serine differentially regulate this enzyme remains elusive. Using kinetic analyses, fluorescence binding, X-ray crystallography, and gel filtration experiments with asparagine, aspartate, and valine as PKM2 ligands, we examined whether the differences in the side-chain polarity of these AAs trigger distinct allosteric responses in PKM2. We found that Asn (polar) and Asp (charged) activate PKM2 and that Val (hydrophobic) inhibits it. The results also indicate that both Asn and Asp can restore the activity of Val-inhibited PKM2. AA-bound crystal structures of PKM2 displayed distinctive interactions within the binding pocket, causing unique allosteric effects in the enzyme. These structure-function analyses of AA-mediated PKM2 regulation shed light on the chemical requirements in the development of mechanism-based small-molecule modulators targeting the AA-binding pocket of PKM2 and provide broader insights into the regulatory mechanisms of complex allosteric enzymes.
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Affiliation(s)
- Suparno Nandi
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242
| | - Mishtu Dey
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242.
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