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Jiang W, Wu Y, Su R, Xu W, Yang W, Qiu Y, Cai Y, Wang C, Hu L, Gu W, Zhu C. Grain-Boundary-Rich Ceria Metallene Nanozyme with Abundant Metal Site Pairs Boosts Phosphatase-like Activity. NANO LETTERS 2024; 24:9635-9642. [PMID: 39077994 DOI: 10.1021/acs.nanolett.4c02394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/31/2024]
Abstract
Natural phosphatases featuring paired metal sites inspire various advanced nanozymes with phosphatase-like activity as alternatives in practical applications. Numerous efforts to create point defects show limited metal site pairs, further resulting in insufficient activity. However, it remains a grand challenge to accurately engineer abundant metal site pairs in nanozymes. Herein, we report a grain-boundary-rich ceria metallene nanozyme (GB-CeO2) with phosphatase-like activity. Grain boundaries acting as the line or interfacial defects can effectively increase the content of Ce4+/Ce3+ site pairs to 72.28%, achieving a 49.28-fold enhancement in activity. Furthermore, abundant grain boundaries optimize the band structure to assist the photoelectron transfer under irradiation, which further increases the content of metal site pairs to 88.96% and finally realizes a 114.39-fold enhanced activity over that of CeO2 without irradiation. Given the different inhibition effects of pesticides on catalysts with and without irradiation, GB-CeO2 was successfully applied to recognize mixed toxic pesticides.
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Affiliation(s)
- Wenxuan Jiang
- State Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Yu Wu
- State Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Rina Su
- State Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Weiqing Xu
- State Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Wenhong Yang
- State Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Yiwei Qiu
- State Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Yujia Cai
- State Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Canglong Wang
- Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000, People's Republic of China
| | - Liuyong Hu
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, Hubei Engineering Technology Research Center of Optoelectronic and New Energy Materials, Wuhan Institute of Technology, Wuhan 430205, People's Republic of China
| | - Wenling Gu
- State Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Chengzhou Zhu
- State Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
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Tripathi A, Dubey KD. The mechanistic insights into different aspects of promiscuity in metalloenzymes. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2024; 141:23-66. [PMID: 38960476 DOI: 10.1016/bs.apcsb.2023.12.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Enzymes are nature's ultimate machinery to catalyze complex reactions. Though enzymes are evolved to catalyze specific reactions, they also show significant promiscuity in reactions and substrate selection. Metalloenzymes contain a metal ion or metal cofactor in their active site, which is crucial in their catalytic activity. Depending on the metal and its coordination environment, the metal ion or cofactor may function as a Lewis acid or base and a redox center and thus can catalyze a plethora of natural reactions. In fact, the versatility in the oxidation state of the metal ions provides metalloenzymes with a high level of catalytic adaptability and promiscuity. In this chapter, we discuss different aspects of promiscuity in metalloenzymes by using several recent experimental and theoretical works as case studies. We start our discussion by introducing the concept of promiscuity and then we delve into the mechanistic insight into promiscuity at the molecular level.
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Affiliation(s)
- Ankita Tripathi
- Department of Chemistry, School of Natural Science, Shiv Nadar Institution of Eminence, Greater Noida, Uttar Pradesh, India
| | - Kshatresh Dutta Dubey
- Department of Chemistry, School of Natural Science, Shiv Nadar Institution of Eminence, Greater Noida, Uttar Pradesh, India.
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Lidbury IDEA, Hitchcock A, Groenhof SRM, Connolly AN, Moushtaq L. New insights in bacterial organophosphorus cycling: From human pathogens to environmental bacteria. Adv Microb Physiol 2024; 84:1-49. [PMID: 38821631 DOI: 10.1016/bs.ampbs.2023.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2024]
Abstract
In terrestrial and aquatic ecosystems, phosphorus (P) availability controls primary production, with consequences for climate regulation and global food security. Understanding the microbial controls on the global P cycle is a prerequisite for minimising our reliance on non-renewable phosphate rock reserves and reducing pollution associated with excessive P fertiliser use. This recognised importance has reinvigorated research into microbial P cycling, which was pioneered over 75 years ago through the study of human pathogenic bacteria-host interactions. Immobilised organic P represents a significant fraction of the total P pool. Hence, microbes have evolved a plethora of mechanisms to transform this fraction into labile inorganic phosphate, the building block for numerous biological molecules. The 'genomics era' has revealed an extraordinary diversity of organic P cycling genes exist in the environment and studies going 'back to the lab' are determining how this diversity relates to function. Through this integrated approach, many hitherto unknown genes and proteins that are involved in microbial P cycling have been discovered. Not only do these fundamental discoveries push the frontier of our knowledge, but several examples also provide exciting opportunities for biotechnology and present possible solutions for improving the sustainability of how we grow our food, both locally and globally. In this review, we provide a comprehensive overview of bacterial organic P cycling, covering studies on human pathogens and how this knowledge is informing new discoveries in environmental microbiology.
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Affiliation(s)
- Ian D E A Lidbury
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom.
| | - Andrew Hitchcock
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom; Plants, Photosynthesis, and Soil, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom
| | - Sophie R M Groenhof
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom
| | - Alex N Connolly
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom
| | - Laila Moushtaq
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom
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Priyanka, Maiti S. Co-assembly-mediated biosupramolecular catalysis: thermodynamic insights into nucleobase specific (oligo)nucleotide attachment and cleavage. J Mater Chem B 2023; 11:10383-10394. [PMID: 37874292 DOI: 10.1039/d3tb01747h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Gaining control over the stability and cleavage of phosphoester and phosphodiester remains a matter of interest for their application in biotechnology to oligonucleotide-based therapeutics. Herein, we report an efficient unactivated phosphoester hydrolysis (stable mono/di/tri/cyclic nucleotide to nucleoside conversion) via a biosupramolecular system comprising of a non-covalent complex of enzyme, alkaline phosphatase (ALP), and Zn(II)-metallosurfactant. We also demonstrate the nucleobase selective activation or inhibition of ALP-mediated oligonucleotide digestion process using that complex. The higher binding affinity of Zn(II)-containing headgroup with phosphate-containing substrate enhanced the effective substrate concentration surrounding the enzyme, which, in turn, results in a drastic decrease in the Michaelis constant (KM), along with an increase in the turnover (kcat). The catalytic activation or inhibition of nucleobase-specific oligonucleotide digestion depends on the hydration, localization of the substrates, and viscosity of the resultant co-assembly upon substrate binding with the enzyme-metallosurfactant complex. Additionally, through isothermal titration calorimetry experiment, we demonstrate enthalpy-entropy change during both the supramolecular binding of (oligo)nucleotides and simultaneous activation/inhibition in catalytic cleavage. Overall, it showed the possible modularity of Zn(II)-mediated biosupramolecular interaction, describing intrinsic thermodynamic aspects in developing complex biocatalytic circuits with nucleobase-specific oligonucleotides inputs, which are relevant in designing nucleic acid-based cargo for drug delivery and bioimaging.
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Affiliation(s)
- Priyanka
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Manauli 140306, India.
| | - Subhabrata Maiti
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Manauli 140306, India.
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Markin CJ, Mokhtari DA, Du S, Doukov T, Sunden F, Cook JA, Fordyce PM, Herschlag D. Decoupling of catalysis and transition state analog binding from mutations throughout a phosphatase revealed by high-throughput enzymology. Proc Natl Acad Sci U S A 2023; 120:e2219074120. [PMID: 37428919 PMCID: PMC10629569 DOI: 10.1073/pnas.2219074120] [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: 11/08/2022] [Accepted: 06/14/2023] [Indexed: 07/12/2023] Open
Abstract
Using high-throughput microfluidic enzyme kinetics (HT-MEK), we measured over 9,000 inhibition curves detailing impacts of 1,004 single-site mutations throughout the alkaline phosphatase PafA on binding affinity for two transition state analogs (TSAs), vanadate and tungstate. As predicted by catalytic models invoking transition state complementary, mutations to active site and active-site-contacting residues had highly similar impacts on catalysis and TSA binding. Unexpectedly, most mutations to more distal residues that reduced catalysis had little or no impact on TSA binding and many even increased tungstate affinity. These disparate effects can be accounted for by a model in which distal mutations alter the enzyme's conformational landscape, increasing the occupancy of microstates that are catalytically less effective but better able to accommodate larger transition state analogs. In support of this ensemble model, glycine substitutions (rather than valine) were more likely to increase tungstate affinity (but not more likely to impact catalysis), presumably due to increased conformational flexibility that allows previously disfavored microstates to increase in occupancy. These results indicate that residues throughout an enzyme provide specificity for the transition state and discriminate against analogs that are larger only by tenths of an Ångström. Thus, engineering enzymes that rival the most powerful natural enzymes will likely require consideration of distal residues that shape the enzyme's conformational landscape and fine-tune active-site residues. Biologically, the evolution of extensive communication between the active site and remote residues to aid catalysis may have provided the foundation for allostery to make it a highly evolvable trait.
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Affiliation(s)
- Craig J. Markin
- Department of Biochemistry, Stanford University, Stanford, CA94305
| | | | - Siyuan Du
- Department of Biochemistry, Stanford University, Stanford, CA94305
- Department of Chemistry, Stanford University, Stanford, CA94305
| | - Tzanko Doukov
- Stanford Synchrotron Radiation Light Source, Stanford Linear Accelerator Centre National Accelerator Laboratory, Menlo Park, CA94025
| | - Fanny Sunden
- Department of Biochemistry, Stanford University, Stanford, CA94305
| | - Jordan A. Cook
- Department of Biochemistry, Stanford University, Stanford, CA94305
| | - Polly M. Fordyce
- ChEM-H Institute, Stanford University, Stanford, CA94305
- Department of Bioengineering, Stanford University, Stanford, CA94305
- Department of Genetics, Stanford University, Stanford, CA94305
- Chan Zuckerberg Biohub, San Francisco, CA94110
| | - Daniel Herschlag
- Department of Biochemistry, Stanford University, Stanford, CA94305
- ChEM-H Institute, Stanford University, Stanford, CA94305
- Department of Chemical Engineering, Stanford University, Stanford, CA94305
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6
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Brown OR, Hullender DA. Biological evolution requires an emergent, self-organizing principle. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023:S0079-6107(23)00058-5. [PMID: 37343790 DOI: 10.1016/j.pbiomolbio.2023.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/16/2023] [Accepted: 06/09/2023] [Indexed: 06/23/2023]
Abstract
In this perspective review, we assess fundamental flaws in Darwinian evolution, including its modern versions. Fixed mutations 'explain' microevolution but not macroevolution including speciation events and the origination of all the major body plans of the Cambrian explosion. Complex, multifactorial change is required for speciation events and inevitably requires self-organization beyond what is accomplished by known mechanisms. The assembly of ribosomes and ATP synthase are specific examples. We propose their origin is a model for what is unexplained in biological evolution. Probability of evolution is modeled in Section 9 and values are absurdly improbable. Speciation and higher taxonomic changes become exponentially less probable as the number of required, genetically-based events increase. Also, the power required of the proposed selection mechanism (survival of the fittest) is nil for any biological advance requiring multiple changes, because they regularly occur in multiple generations (different genomes) and would not be selectively conserved by the concept survival of the fittest (a concept ultimately centered on the individual). Thus, survival of the fittest cannot 'explain' the origin of the millions of current and extinct species. We also focus on the inadequacies of laboratory chemistry to explain the complex, required biological self-organization seen in cells. We propose that a 'bioelectromagnetic' field/principle emerges in living cells. Synthesis by self-organization of massive molecular complexes involves biochemical responses to this emergent field/principle. There are ramifications for philosophy, science, and religion. Physics and mathematics must be more strongly integrated with biology and integration should receive dedicated funding with special emphasis for medical applications; treatment of cancer and genetic diseases are examples.
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Affiliation(s)
- Olen R Brown
- Emeritus of Biomedical Sciences, at the University of Missouri, Columbia, MO, USA.
| | - David A Hullender
- Mechanical and Aerospace Engineering at the University of Texas at Arlington, USA
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Deng J, Cui Q. Second-Shell Residues Contribute to Catalysis by Predominately Preorganizing the Apo State in PafA. J Am Chem Soc 2023; 145:11333-11347. [PMID: 37172218 PMCID: PMC10810092 DOI: 10.1021/jacs.3c02423] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Residues beyond the first coordination shell are often observed to make considerable cumulative contributions in enzymes. Due to typically indirect perturbations of multiple physicochemical properties of the active site, however, their individual and specific roles in enzyme catalysis and disease-causing mutations remain difficult to predict and understand at the molecular level. Here we analyze the contributions of several second-shell residues in phosphate-irrepressible alkaline phosphatase of flavobacterium (PafA), a representative system as one of the most efficient enzymes. By adopting a multifaceted approach that integrates quantum-mechanical/molecular-mechanical free energy computations, molecular-mechanical molecular dynamics simulations, and density functional theory cluster model calculations, we probe the rate-limiting phosphoryl transfer step and structural properties of all relevant enzyme states. In combination with available experimental data, our computational results show that mutations of the studied second-shell residues impact catalytic efficiency mainly by perturbation of the apo state and therefore substrate binding, while they do not affect the ground state or alter the nature of phosphoryl transfer transition state significantly. Several second-shell mutations also modulate the active site hydration level, which in turn influences the energetics of phosphoryl transfer. These mechanistic insights also help inform strategies that may improve the efficiency of enzyme design and engineering by going beyond the current focus on the first coordination shell.
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Affiliation(s)
- Jiahua Deng
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Qiang Cui
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
- Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, Massachusetts 02215, United States
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8
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Bihani SC, Nagar V, Kumar M. Mechanistic and evolutionary insights into alkaline phosphatase superfamily through structure-function studies on Sphingomonas alkaline phosphatase. Arch Biochem Biophys 2023; 736:109524. [PMID: 36716801 DOI: 10.1016/j.abb.2023.109524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 12/20/2022] [Accepted: 01/20/2023] [Indexed: 01/28/2023]
Abstract
Alkaline phosphatases (APs), represented by E. coli AP (ECAP), employ an arginine residue to stabilize the phosphoryl group in the active site; whereas, AP from Sphingomonas (SPAP) shows a unique combination of substrate-binding residues; Thr89, Asn110, Lys171, and Arg173. Although such combination has been observed only in SPAP, these residues are present separately in different members of the AP superfamily. Here, we establish the presence of two distinct classes of APs; ECAP-type and SPAP-type. Bioinformatic analyses show that SPAP-type of APs are widely distributed in the bacterial kingdom. The role of active site residues in the catalytic mechanism has been delineated through a set of crystal structures reported here. These structures, representing different stages of the reaction pathway provide wealth of information for the catalytic mechanism. Despite critical differences in the substrate binding residues, SPAP follows a mechanism similar to that of ECAP-type of APs. Structure-based phylogenetic analysis suggests that SPAP and ECAP may have diverged very early during the evolution from a common ancestor. Moreover, it is proposed that the SPAP-type of APs are fundamental members of the AP superfamily and are more closely related to other members of the superfamily as compared to the ECAP-type of APs.
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Affiliation(s)
- Subhash C Bihani
- Protein Crystallography Section, Radiation Biology & Health Sciences Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India.
| | - Vandan Nagar
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India; Food Microbiology Group, Food Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Mukesh Kumar
- Protein Crystallography Section, Radiation Biology & Health Sciences Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India
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9
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Schmitz C, Madej M, Nowakowska Z, Cuppari A, Jacula A, Ksiazek M, Mikruta K, Wisniewski J, Pudelko-Malik N, Saran A, Zeytuni N, Mlynarz P, Lamont RJ, Usón I, Siksnys V, Potempa J, Solà M. Response regulator PorX coordinates oligonucleotide signalling and gene expression to control the secretion of virulence factors. Nucleic Acids Res 2022; 50:12558-12577. [PMID: 36464236 PMCID: PMC9757075 DOI: 10.1093/nar/gkac1103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 10/27/2022] [Accepted: 11/08/2022] [Indexed: 12/07/2022] Open
Abstract
The PglZ family of proteins belongs to the alkaline phosphatase superfamily, which consists of metallohydrolases with limited sequence identity but similar metal-coordination architectures in otherwise divergent active sites. Proteins with a well-defined PglZ domain are ubiquitous among prokaryotes as essential components of BREX phage defence systems and two-component systems (TCSs). Whereas other members of the alkaline phosphatase superfamily are well characterized, the activity, structure and biological function of PglZ family proteins remain unclear. We therefore investigated the structure and function of PorX, an orphan response regulator of the Porphyromonas gingivalis TCS containing a putative PglZ effector domain. The crystal structure of PorX revealed a canonical receiver domain, a helical bundle, and an unprecedented PglZ domain, similar to the general organization of the phylogenetically related BREX-PglZ proteins. The PglZ domain of PorX features an active site cleft suitable for large substrates. An extensive search for substrates revealed that PorX is a phosphodiesterase that acts on cyclic and linear oligonucleotides, including signalling molecules such as cyclic oligoadenylates. These results, combined with mutagenesis, biophysical and enzymatic analysis, suggest that PorX coordinates oligonucleotide signalling pathways and indirectly regulates gene expression to control the secretion of virulence factors.
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Affiliation(s)
- Claus Schmitz
- Department of Structural Biology, Molecular Biology Institute of Barcelona, CSIC, Barcelona Science Park, Barcelona E-08028, Spain
| | - Mariusz Madej
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków PL-30-387, Poland
| | - Zuzanna Nowakowska
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków PL-30-387, Poland
| | - Anna Cuppari
- Department of Structural Biology, Molecular Biology Institute of Barcelona, CSIC, Barcelona Science Park, Barcelona E-08028, Spain
| | - Anna Jacula
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków PL-30-387, Poland
| | - Miroslaw Ksiazek
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków PL-30-387, Poland
| | - Katarzyna Mikruta
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków PL-30-387, Poland
| | - Jerzy Wisniewski
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wroclaw University of Science and Technology, Wroclaw PL-50-370, Poland
| | - Natalia Pudelko-Malik
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wroclaw University of Science and Technology, Wroclaw PL-50-370, Poland
| | - Anshu Saran
- Department of Anatomy and Cell Biology, McGill University, Montréal, Quebec H3A 0C7, Canada
| | - Natalie Zeytuni
- Department of Anatomy and Cell Biology, McGill University, Montréal, Quebec H3A 0C7, Canada
| | - Piotr Mlynarz
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wroclaw University of Science and Technology, Wroclaw PL-50-370, Poland
| | - Richard J Lamont
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, KY 40202, USA
| | - Isabel Usón
- Department of Structural Biology, Molecular Biology Institute of Barcelona, CSIC, Barcelona Science Park, Barcelona E-08028, Spain
- ICREA Institució Catalana de Recerca i Estudis Avançats, Barcelona E-08010, Spain
| | - Virginijus Siksnys
- Institute of Biotechnology, Vilnius University, Vilnius 10257, Lithuania
| | - Jan Potempa
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków PL-30-387, Poland
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, KY 40202, USA
| | - Maria Solà
- Department of Structural Biology, Molecular Biology Institute of Barcelona, CSIC, Barcelona Science Park, Barcelona E-08028, Spain
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Yeniterzi D, Demirsoy Z, Saylam A, Özçubukçu S, Gülseren G. Nanoarchitectonics of Fullerene Based Enzyme Mimics for Osteogenic Induction of Stem Cells. Macromol Biosci 2022; 22:e2200079. [PMID: 35751428 DOI: 10.1002/mabi.202200079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 06/10/2022] [Indexed: 11/06/2022]
Abstract
Enzyme mimicry is a topic of considerable interest in the development of multifunctional biomimetic materials. Mimicking enzyme activity is a major challenge in biomaterials research, and artificial analogs that simultaneously recapitulate the catalytic and metabolic activity of native enzymes are considered to be the ultimate goal of this field. This consensus may be challenged by self-assembling multifunctional nanostructures to develop close-to-fidelity enzyme mimics. Here, we present the ability of fullerene nanostructures decorated with active units to form enzyme-like materials that can mimic phosphatases in a metal-free manner. These nanostructures self-assemble into nanoclusters forming multiple random active sites that can cleave both phosphomonoesters and phosphodiesters while being more specific for the phosphomonoesters. Moreover, they are reusable and show an increase in catalytic activity over multiple cycles similar to their natural counterparts. In addition to having enzyme-like catalytic properties, these nanocatalysts imitate the biological functions of their natural analogs by inducing biomineralization and osteoinduction in preosteoblast and mesenchymal stem cells in vitro studies. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Dilara Yeniterzi
- Graduate School of Natural & Applied Sciences, Konya Food and Agriculture University, Konya, 42080, Turkey
| | - Zeynep Demirsoy
- Graduate School of Natural & Applied Sciences, Konya Food and Agriculture University, Konya, 42080, Turkey
| | - Aytül Saylam
- Department of Chemistry, Middle East Technical University, Ankara, 06800, Turkey
| | - Salih Özçubukçu
- Department of Chemistry, Middle East Technical University, Ankara, 06800, Turkey
| | - Gülcihan Gülseren
- Graduate School of Natural & Applied Sciences, Konya Food and Agriculture University, Konya, 42080, Turkey.,Department of Molecular Biology and Genetics, Konya Food and Agriculture University, Konya, 42080, Turkey
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A widely distributed phosphate-insensitive phosphatase presents a route for rapid organophosphorus remineralization in the biosphere. Proc Natl Acad Sci U S A 2022; 119:2118122119. [PMID: 35082153 PMCID: PMC8812569 DOI: 10.1073/pnas.2118122119] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/11/2021] [Indexed: 11/24/2022] Open
Abstract
At several locations across the globe, terrestrial and marine primary production, which underpin global food security, biodiversity, and climate regulation, are limited by inorganic phosphate availability. A major fraction of the total phosphorus pool exists in organic form, requiring mineralization to phosphate by enzymes known as phosphatases prior to incorporation into cellular biomolecules. Phosphatases are typically synthesized in response to phosphate depletion, assisting with phosphorus acquisition. Here, we reveal that a unique bacterial phosphatase, PafA, is widely distributed in the biosphere and has a distinct functional role in carbon acquisition, releasing phosphate as a by-product. PafA, therefore, represents an overlooked mechanism in the global phosphorus cycle and a hitherto cryptic route for the regeneration of bioavailable phosphorus in nature. The regeneration of bioavailable phosphate from immobilized organophosphorus represents a key process in the global phosphorus cycle and is facilitated by enzymes known as phosphatases. Most bacteria possess at least one of three phosphatases with broad substrate specificity, known as PhoA, PhoX, and PhoD, whose activity is optimal under alkaline conditions. The production and activity of these phosphatases is repressed by phosphate availability. Therefore, they are only fully functional when bacteria experience phosphorus-limiting growth conditions. Here, we reveal a previously overlooked phosphate-insensitive phosphatase, PafA, prevalent in Bacteroidetes, which is highly abundant in nature and represents a major route for the regeneration of environmental phosphate. Using the enzyme from Flavobacterium johnsoniae, we show that PafA is highly active toward phosphomonoesters, is fully functional in the presence of excess phosphate, and is essential for growth on phosphorylated carbohydrates as a sole carbon source. These distinct properties of PafA may expand the metabolic niche of Bacteroidetes by enabling the utilization of abundant organophosphorus substrates as C and P sources, providing a competitive advantage when inhabiting zones of high microbial activity and nutrient demand. PafA, which is constitutively synthesized by soil and marine flavobacteria, rapidly remineralizes phosphomonoesters releasing bioavailable phosphate that can be acquired by neighboring cells. The pafA gene is highly diverse in plant rhizospheres and is abundant in the global ocean, where it is expressed independently of phosphate availability. PafA therefore represents an important enzyme in the context of global biogeochemical cycling and has potential applications in sustainable agriculture.
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12
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Mu X, Jiang X, Zhang Y, Liu X, Zhang S, Wang W, Huang Y, Ma P, Song D. Sensitive ratiometric fluorescence probe based on chitosan carbon dots and calcein for Alkaline phosphatase detection and bioimaging in cancer cells. Anal Chim Acta 2021; 1188:339163. [PMID: 34794579 DOI: 10.1016/j.aca.2021.339163] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/04/2021] [Accepted: 10/08/2021] [Indexed: 12/18/2022]
Abstract
Alkaline phosphatase (ALP) is a commonly used marker in clinical practice, and this enzyme is a key indicator for diagnosing various diseases. In this study, we describe the development of a reliable and novel fluorescent assay for ALP detection based on chitosan carbon dots (C-CDs, peak emission, 412 nm) and calcein (peak emission, 512 nm). In the presence of Eu3+ (which binds calcein), the fluorescence intensity of calcein is quenched. Utilizing the ALP-triggered generation of phosphate ions (PO43-) from the substrate p-nitrophenyl phosphate (pNPP), the Eu3+ ions bind PO43- (which shows a higher affinity toward Eu3+ than calcein), and the fluorescence of calcein is recovered. As a consequence, C-CDs fluorescence is decreased by inner filter effect (IFE). Exploiting these changes in the fluorescence intensity ratio of C-CDs and calcein, we developed a high sensitivity, accurate, and easily synthesized ratiometric fluorescence probe. Our novel fluorescent bioassay demonstrates good linear relationship in the 0.09-0.8 mU mL-1 range, with a low detection limit of 0.013 mU mL-1. The excellent applicability of this novel assay in HepG2 cells and human serum samples demonstrates that our novel method has excellent biomedical research and disease diagnosis prospects.
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Affiliation(s)
- Xiaowei Mu
- College of Chemistry, Jilin University, Qianjin Street 2699, Changchun, 130012, China
| | - Xue Jiang
- College of Life Sciences, Jilin University, Qianjin Street 2699, Changchun, 130012, China
| | - Yu Zhang
- College of Life Sciences, Jilin University, Qianjin Street 2699, Changchun, 130012, China
| | - Xin Liu
- College of Chemistry, Jilin University, Qianjin Street 2699, Changchun, 130012, China
| | - Siqi Zhang
- College of Chemistry, Jilin University, Qianjin Street 2699, Changchun, 130012, China
| | - Wei Wang
- College of Chemistry, Jilin University, Qianjin Street 2699, Changchun, 130012, China
| | - Yibing Huang
- College of Life Sciences, Jilin University, Qianjin Street 2699, Changchun, 130012, China
| | - Pinyi Ma
- College of Chemistry, Jilin University, Qianjin Street 2699, Changchun, 130012, China.
| | - Daqian Song
- College of Chemistry, Jilin University, Qianjin Street 2699, Changchun, 130012, China.
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13
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Mokhtari DA, Appel MJ, Fordyce PM, Herschlag D. High throughput and quantitative enzymology in the genomic era. Curr Opin Struct Biol 2021; 71:259-273. [PMID: 34592682 PMCID: PMC8648990 DOI: 10.1016/j.sbi.2021.07.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 07/23/2021] [Indexed: 12/28/2022]
Abstract
Accurate predictions from models based on physical principles are the ultimate metric of our biophysical understanding. Although there has been stunning progress toward structure prediction, quantitative prediction of enzyme function has remained challenging. Realizing this goal will require large numbers of quantitative measurements of rate and binding constants and the use of these ground-truth data sets to guide the development and testing of these quantitative models. Ground truth data more closely linked to the underlying physical forces are also desired. Here, we describe technological advances that enable both types of ground truth measurements. These advances allow classic models to be tested, provide novel mechanistic insights, and place us on the path toward a predictive understanding of enzyme structure and function.
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Affiliation(s)
- D A Mokhtari
- Department of Biochemistry, Stanford University, Stanford, CA, 94305, USA
| | - M J Appel
- Department of Biochemistry, Stanford University, Stanford, CA, 94305, USA
| | - P M Fordyce
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA; ChEM-H Institute, Stanford University, Stanford, CA, 94305, USA; Department of Genetics, Stanford University, Stanford, CA, 94305, USA; Chan Zuckerberg Biohub San Francisco, CA, 94110, USA.
| | - D Herschlag
- Department of Biochemistry, Stanford University, Stanford, CA, 94305, USA; Department of Chemical Engineering, Stanford University, Stanford, CA, 94305, USA; ChEM-H Institute, Stanford University, Stanford, CA, 94305, USA.
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14
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Srivastava A, Saavedra DEM, Thomson B, García JAL, Zhao Z, Patrick WM, Herndl GJ, Baltar F. Enzyme promiscuity in natural environments: alkaline phosphatase in the ocean. THE ISME JOURNAL 2021; 15:3375-3383. [PMID: 34050259 PMCID: PMC8528806 DOI: 10.1038/s41396-021-01013-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 05/07/2021] [Accepted: 05/12/2021] [Indexed: 02/03/2023]
Abstract
Alkaline phosphatase (APase) is one of the marine enzymes used by oceanic microbes to obtain inorganic phosphorus (Pi) from dissolved organic phosphorus to overcome P-limitation. Marine APase is generally recognized to perform P-monoesterase activity. Here we integrated a biochemical characterization of a specific APase enzyme, examination of global ocean databases, and field measurements, to study the type and relevance of marine APase promiscuity. We performed an in silico mining of phoA homologs, followed by de novo synthesis and heterologous expression in E. coli of the full-length gene from Alteromonas mediterranea, resulting in a recombinant PhoA. A global analysis using the TARA Oceans, Malaspina and other metagenomic databases confirmed the predicted widespread distribution of the gene encoding the targeted PhoA in all oceanic basins throughout the water column. Kinetic assays with the purified PhoA enzyme revealed that this enzyme exhibits not only the predicted P-monoester activity, but also P-diesterase, P-triesterase and sulfatase activity as a result of a promiscuous behavior. Among all activities, P-monoester bond hydrolysis exhibited the highest catalytic activity of APase despite its lower affinity for phosphate monoesters. APase is highly efficient as a P-monoesterase at high substrate concentrations, whereas promiscuous activities of APase, like diesterase, triesterase, and sulfatase activities are more efficient at low substrate concentrations. Strong similarities were observed between the monoesterase:diesterase ratio of the purified PhoA protein in the laboratory and in natural seawater. Thus, our results reveal enzyme promiscuity of APase playing potentially an important role in the marine phosphorus cycle.
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Affiliation(s)
- Abhishek Srivastava
- grid.10420.370000 0001 2286 1424Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria
| | - Daniel E. M. Saavedra
- grid.10420.370000 0001 2286 1424Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria
| | - Blair Thomson
- grid.29980.3a0000 0004 1936 7830Department of Marine Science, University of Otago, Dunedin, New Zealand
| | - Juan A. L. García
- grid.10420.370000 0001 2286 1424Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria
| | - Zihao Zhao
- grid.10420.370000 0001 2286 1424Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria
| | - Wayne M. Patrick
- grid.267827.e0000 0001 2292 3111School of Biological Sciences, Victoria University of Wellington, Kelburn, New Zealand
| | - Gerhard J. Herndl
- grid.10420.370000 0001 2286 1424Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria ,grid.5477.10000000120346234NIOZ, Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research, Utrecht University, Texel, The Netherlands
| | - Federico Baltar
- grid.10420.370000 0001 2286 1424Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria ,grid.29980.3a0000 0004 1936 7830Department of Marine Science, University of Otago, Dunedin, New Zealand
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15
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Markin CJ, Mokhtari DA, Sunden F, Appel MJ, Akiva E, Longwell SA, Sabatti C, Herschlag D, Fordyce PM. Revealing enzyme functional architecture via high-throughput microfluidic enzyme kinetics. Science 2021; 373:373/6553/eabf8761. [PMID: 34437092 DOI: 10.1126/science.abf8761] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 05/24/2021] [Indexed: 12/21/2022]
Abstract
Systematic and extensive investigation of enzymes is needed to understand their extraordinary efficiency and meet current challenges in medicine and engineering. We present HT-MEK (High-Throughput Microfluidic Enzyme Kinetics), a microfluidic platform for high-throughput expression, purification, and characterization of more than 1500 enzyme variants per experiment. For 1036 mutants of the alkaline phosphatase PafA (phosphate-irrepressible alkaline phosphatase of Flavobacterium), we performed more than 670,000 reactions and determined more than 5000 kinetic and physical constants for multiple substrates and inhibitors. We uncovered extensive kinetic partitioning to a misfolded state and isolated catalytic effects, revealing spatially contiguous regions of residues linked to particular aspects of function. Regions included active-site proximal residues but extended to the enzyme surface, providing a map of underlying architecture not possible to derive from existing approaches. HT-MEK has applications that range from understanding molecular mechanisms to medicine, engineering, and design.
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Affiliation(s)
- C J Markin
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA
| | - D A Mokhtari
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA
| | - F Sunden
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA
| | - M J Appel
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA
| | - E Akiva
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158, USA
| | - S A Longwell
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - C Sabatti
- Department of Biomedical Data Science, Stanford University, Stanford, CA 94305, USA.,Department of Statistics, Stanford University, Stanford, CA 94305, USA
| | - D Herschlag
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA. .,Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.,ChEM-H Institute, Stanford University, Stanford, CA 94305, USA
| | - P M Fordyce
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA. .,ChEM-H Institute, Stanford University, Stanford, CA 94305, USA.,Department of Genetics, Stanford University, Stanford, CA 94305, USA.,Chan Zuckerberg Biohub; San Francisco, CA 94110, USA
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16
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Niche-adaptation in plant-associated Bacteroidetes favours specialisation in organic phosphorus mineralisation. THE ISME JOURNAL 2021; 15:1040-1055. [PMID: 33257812 PMCID: PMC8115612 DOI: 10.1038/s41396-020-00829-2] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/30/2020] [Indexed: 02/07/2023]
Abstract
Bacteroidetes are abundant pathogen-suppressing members of the plant microbiome that contribute prominently to rhizosphere phosphorus mobilisation, a frequent growth-limiting nutrient in this niche. However, the genetic traits underpinning their success in this niche remain largely unknown, particularly regarding their phosphorus acquisition strategies. By combining cultivation, multi-layered omics and biochemical analyses we first discovered that all plant-associated Bacteroidetes express constitutive phosphatase activity, linked to the ubiquitous possession of a unique phosphatase, PafA. For the first time, we also reveal a subset of Bacteroidetes outer membrane SusCD-like complexes, typically associated with carbon acquisition, and several TonB-dependent transporters, are induced during Pi-depletion. Furthermore, in response to phosphate depletion, the plant-associated Flavobacterium used in this study expressed many previously characterised and novel proteins targeting organic phosphorus. Collectively, these enzymes exhibited superior phosphatase activity compared to plant-associated Pseudomonas spp. Importantly, several of the novel low-Pi-inducible phosphatases and transporters, belong to the Bacteroidetes auxiliary genome and are an adaptive genomic signature of plant-associated strains. In conclusion, niche adaptation to the plant microbiome thus appears to have resulted in the acquisition of unique phosphorus scavenging loci in Bacteroidetes, enhancing their phosphorus acquisition capabilities. These traits may enable their success in the rhizosphere and also present exciting avenues to develop sustainable agriculture.
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17
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Kerk D, Valdés-Tresanco ME, Toth R, Noskov SY, Ng KKS, Moorhead GB. Origin of the Phosphoprotein Phosphatase (PPP) sequence family in Bacteria: Critical ancestral sequence changes, radiation patterns and substrate binding features. BBA ADVANCES 2021; 1:100005. [PMID: 37082010 PMCID: PMC10074919 DOI: 10.1016/j.bbadva.2021.100005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Background Phosphoprotein phosphatases (PPP) belong to the PPP Sequence family, which in turn belongs to the broader metallophosphoesterase (MPE) superfamily. The relationship between the PPP Sequence family and other members of the MPE superfamily remains unresolved, in particular what transitions took place in an ancestral MPE to ultimately produce the phosphoprotein specific phosphatases (PPPs). Methods We use structural and sequence alignment data, phylogenetic tree analysis, sequence signature (Weblogo) analysis, in silico protein-peptide modeling data, and in silico mutagenesis to trace a likely route of evolution from MPEs to the PPP Sequence family. Hidden Markov Model (HMM) based iterative database search strategies were utilized to identify PPP Sequence Family members from numerous bacterial groups. Results Using Mre11 as proxy for an ancestral nuclease-like MPE we trace a possible evolutionary route that alters a single active site substrate binding His-residue to yield a new substrate binding accessory, the "2-Arg-Clamp". The 2-Arg-Clamp is not found in MPEs, but is present in all PPP Sequence family members, where the phosphomonesterase reaction predominates. Variation in position of the clamp arginines and a supplemental sequence loop likely provide substrate specificity for each PPP Sequence family group. Conclusions Loss of a key substrate binding His-in MPEs opened the path to bind novel substrates and evolution of the 2-Arg-Clamp, a sequence change seen in both bacterial and eukaryotic phosphoprotein phosphatases.General significance: We establish a likely evolutionary route from nuclease-like MPE to PPP Sequence family enzymes, that includes the phosphoprotein phosphatases.
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18
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Borosky GL. Alkaline Phosphatases: in Silico Study on the Catalytic Effect of Conserved Active Site Residues Using Human Placental Alkaline Phosphatase (PLAP) As a Model Protein. J Chem Inf Model 2020; 60:6228-6241. [PMID: 33306371 DOI: 10.1021/acs.jcim.0c00860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The metalloenzymes from the alkaline phosphatase (AP) superfamily catalyze the hydrolysis and transphosphorylation of phosphate monoesters. The role of several amino acids highly conserved in the active site of this family of enzymes was examined, using human placental AP (PLAP) as a model protein. By employing an active-site model based on the X-ray crystal structure of PLAP, mutations of several key residues were modeled by quantum mechanical methods in order to determine their impact on the catalytic activity. Kinetic and thermodynamic estimations were achieved for each reaction step of the catalytic mechanism by characterization of the intermediates and transition states on the reaction pathway, and the effects of mutations on the activation barriers were analyzed. A good accordance was observed between the present computational results and experimental measurements reported in the literature.
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Affiliation(s)
- Gabriela L Borosky
- INFIQC, CONICET and Departamento de Química Teórica y Computacional, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba 5000, Argentina
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19
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Gabale U, Peña Palomino PA, Kim H, Chen W, Ressl S. The essential inner membrane protein YejM is a metalloenzyme. Sci Rep 2020; 10:17794. [PMID: 33082366 PMCID: PMC7576196 DOI: 10.1038/s41598-020-73660-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 09/18/2020] [Indexed: 12/27/2022] Open
Abstract
Recent recurrent outbreaks of Gram-negative bacteria show the critical need to target essential bacterial mechanisms to fight the increase of antibiotic resistance. Pathogenic Gram-negative bacteria have developed several strategies to protect themselves against the host immune response and antibiotics. One such strategy is to remodel the outer membrane where several genes are involved. yejM was discovered as an essential gene in E. coli and S. typhimurium that plays a critical role in their virulence by changing the outer membrane permeability. How the inner membrane protein YejM with its periplasmic domain changes membrane properties remains unknown. Despite overwhelming structural similarity between the periplasmic domains of two YejM homologues with hydrolases like arylsulfatases, no enzymatic activity has been previously reported for YejM. Our studies reveal an intact active site with bound metal ions in the structure of YejM periplasmic domain. Furthermore, we show that YejM has a phosphatase activity that is dependent on the presence of magnesium ions and is linked to its function of regulating outer membrane properties. Understanding the molecular mechanism by which YejM is involved in outer membrane remodeling will help to identify a new drug target in the fight against the increased antibiotic resistance.
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Affiliation(s)
- Uma Gabale
- Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, 212 S Hawthrone Dr, Bloomington, IN, 47405, USA.
| | - Perla Arianna Peña Palomino
- Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, 212 S Hawthrone Dr, Bloomington, IN, 47405, USA
| | - HyunAh Kim
- Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, 212 S Hawthrone Dr, Bloomington, IN, 47405, USA
| | - Wenya Chen
- Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, 212 S Hawthrone Dr, Bloomington, IN, 47405, USA
| | - Susanne Ressl
- Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, 212 S Hawthrone Dr, Bloomington, IN, 47405, USA.
- Department of Neuroscience, The University of Texas At Austin, 100 E. 24th St., NHB 2.504, Austin, TX, 78712, USA.
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20
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Ambreen S, Yasmin A, Aziz S. Isolation and characterization of organophosphorus phosphatases from Bacillus thuringiensis MB497 capable of degrading Chlorpyrifos, Triazophos and Dimethoate. Heliyon 2020; 6:e04221. [PMID: 32642578 PMCID: PMC7334429 DOI: 10.1016/j.heliyon.2020.e04221] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/10/2020] [Accepted: 06/11/2020] [Indexed: 01/03/2023] Open
Abstract
In the current investigation, bacterial strain Bacillus thuringiensis MB497 was examined for production of intracellular and extracellular organophosphorus phosphatase (OPP) enzymes. This strain produced significant amount of extracellular acidic and alkaline phosphatases. Production of neutral phosphatase was negligible. Production of OPP was generally highest at pH 11 and at 45-50 °C. However, activity and stability of OPP was highest at 37 °C and reduced at higher temperatures. OPP production was decreased after 48 h of incubation. Largely, OPP activity was inhibited by SDS and EDTA and significantly enhanced by metals (Zn++, Cu++ and Cd++). Both acidic and alkaline OPPs were capable of bio-precipitation of selected metals (Ni, Mn, Cr and Cd) up to 86-100%. When used against 50 mg/l of three OP pesticides (Chlorpyrifos, Triazophos, and Dimethoate), 81-94.6% degradation of pesticides was observed by alkaline OPP, while acidic OPP showed less degradation (61-70.5%) within 30 min of incubation.
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Affiliation(s)
- Samina Ambreen
- Microbiology & Biotechnology Research Lab, Department of Environmental Sciences, Fatima Jinnah Women University, The Mall, Rawalpindi, Pakistan
| | - Azra Yasmin
- Microbiology & Biotechnology Research Lab, Department of Environmental Sciences, Fatima Jinnah Women University, The Mall, Rawalpindi, Pakistan
| | - Satara Aziz
- Microbiology & Biotechnology Research Lab, Department of Environmental Sciences, Fatima Jinnah Women University, The Mall, Rawalpindi, Pakistan
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21
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Lukesch M, Tasnádi G, Ditrich K, Hall M, Faber K. Characterization of alkaline phosphatase PhoK from Sphingomonas sp. BSAR-1 for phosphate monoester synthesis and hydrolysis. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140291. [DOI: 10.1016/j.bbapap.2019.140291] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 10/04/2019] [Accepted: 10/10/2019] [Indexed: 12/11/2022]
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22
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Komazin G, Maybin M, Woodard RW, Scior T, Schwudke D, Schombel U, Gisch N, Mamat U, Meredith TC. Substrate structure-activity relationship reveals a limited lipopolysaccharide chemotype range for intestinal alkaline phosphatase. J Biol Chem 2019; 294:19405-19423. [PMID: 31704704 DOI: 10.1074/jbc.ra119.010836] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 10/31/2019] [Indexed: 12/21/2022] Open
Abstract
Lipopolysaccharide (LPS) from the Gram-negative bacterial outer membrane potently activates the human innate immune system. LPS is recognized by the Toll-like receptor 4/myeloid differentiation factor-2 (TLR4/MD2) complex, leading to the release of pro-inflammatory cytokines. Alkaline phosphatase (AP) is currently being investigated as an anti-inflammatory agent for detoxifying LPS through dephosphorylating lipid A, thus providing a potential treatment for managing both acute (sepsis) and chronic (metabolic endotoxemia) pathologies wherein aberrant TLR4/MD2 activation has been implicated. Endogenous LPS preparations are chemically heterogeneous, and little is known regarding the LPS chemotype substrate range of AP. Here, we investigated the activity of AP on a panel of structurally defined LPS chemotypes isolated from Escherichia coli and demonstrate that calf intestinal AP (cIAP) has only minimal activity against unmodified enteric LPS chemotypes. Pi was only released from a subset of LPS chemotypes harboring spontaneously labile phosphoethanolamine (PEtN) modifications connected through phosphoanhydride bonds. We demonstrate that the spontaneously hydrolyzed O-phosphorylethanolamine is the actual substrate for AP. We found that the 1- and 4'-lipid A phosphate groups critical in TLR4/MD2 signaling become susceptible to hydrolysis only after de-O-acylation of ester linked primary acyl chains on lipid A. Furthermore, PEtN modifications on lipid A specifically enhanced hTLR4 agonist activity of underacylated LPS preparations. Computational binding models are proposed to explain the limitation of AP substrate specificity imposed by the acylation state of lipid A, and the mechanism of PEtN in enhancing hTLR4/MD2 signaling.
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Affiliation(s)
- Gloria Komazin
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Michael Maybin
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Ronald W Woodard
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109
| | - Thomas Scior
- Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72000, Mexico
| | - Dominik Schwudke
- Bioanalytical Chemistry, Priority Research Area Infections, Research Center Borstel, Leibniz Lung Center, 23845 Borstel, Germany
| | - Ursula Schombel
- Bioanalytical Chemistry, Priority Research Area Infections, Research Center Borstel, Leibniz Lung Center, 23845 Borstel, Germany
| | - Nicolas Gisch
- Bioanalytical Chemistry, Priority Research Area Infections, Research Center Borstel, Leibniz Lung Center, 23845 Borstel, Germany
| | - Uwe Mamat
- Cellular Microbiology, Priority Research Area Infections, Research Center Borstel, Leibniz Lung Center, 23845 Borstel, Germany
| | - Timothy C Meredith
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
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23
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Dasgupta S, Aullón G, Zangrando E, Das D. Mapping the working route of phosphate monoester hydrolysis catalyzed by copper based models with special emphasis on the role of oxoanions by experimental and theoretical studies. NEW J CHEM 2019. [DOI: 10.1039/c8nj04018d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The mechanistic pathway of phosphate-ester bond hydrolysis with special emphasis on the role of oxoanions was explored by experimental and theoretical study.
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Affiliation(s)
| | - Gabriel Aullón
- Departament de Química Inorgànica i Orgànica (Secció de Química Inorgànica) and Institut de QuímicaTeorica i Computacional
- Universitat de Barcelona
- 08028 Barcelona
- Spain
| | - Ennio Zangrando
- Department of Chemical and Pharmaceutical Sciences
- University of Trieste
- 34127 Trieste
- Italy
| | - Debasis Das
- Department of Chemistry
- University of Calcutta
- Kolkata 700009
- India
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24
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van Loo B, Bayer CD, Fischer G, Jonas S, Valkov E, Mohamed MF, Vorobieva A, Dutruel C, Hyvönen M, Hollfelder F. Balancing Specificity and Promiscuity in Enzyme Evolution: Multidimensional Activity Transitions in the Alkaline Phosphatase Superfamily. J Am Chem Soc 2018; 141:370-387. [PMID: 30497259 DOI: 10.1021/jacs.8b10290] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Highly proficient, promiscuous enzymes can be springboards for functional evolution, able to avoid loss of function during adaptation by their capacity to promote multiple reactions. We employ a systematic comparative study of structure, sequence, and substrate specificity to track the evolution of specificity and reactivity between promiscuous members of clades of the alkaline phosphatase (AP) superfamily. Construction of a phylogenetic tree of protein sequences maps out the likely transition zone between arylsulfatases (ASs) and phosphonate monoester hydrolases (PMHs). Kinetic analysis shows that all enzymes characterized have four chemically distinct phospho- and sulfoesterase activities, with rate accelerations ranging from 1011- to 1017-fold for their primary and 109- to 1012-fold for their promiscuous reactions, suggesting that catalytic promiscuity is widespread in the AP-superfamily. This functional characterization and crystallography reveal a novel class of ASs that is so similar in sequence to known PMHs that it had not been recognized as having diverged in function. Based on analysis of snapshots of catalytic promiscuity "in transition", we develop possible models that would allow functional evolution and determine scenarios for trade-off between multiple activities. For the new ASs, we observe largely invariant substrate specificity that would facilitate the transition from ASs to PMHs via trade-off-free molecular exaptation, that is, evolution without initial loss of primary activity and specificity toward the original substrate. This ability to bypass low activity generalists provides a molecular solution to avoid adaptive conflict.
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Affiliation(s)
- Bert van Loo
- Department of Biochemistry , University of Cambridge , Cambridge CB2 1GA , United Kingdom
| | - Christopher D Bayer
- Department of Biochemistry , University of Cambridge , Cambridge CB2 1GA , United Kingdom
| | - Gerhard Fischer
- Department of Biochemistry , University of Cambridge , Cambridge CB2 1GA , United Kingdom
| | - Stefanie Jonas
- Department of Biochemistry , University of Cambridge , Cambridge CB2 1GA , United Kingdom
| | - Eugene Valkov
- Department of Biochemistry , University of Cambridge , Cambridge CB2 1GA , United Kingdom
| | - Mark F Mohamed
- Department of Biochemistry , University of Cambridge , Cambridge CB2 1GA , United Kingdom
| | - Anastassia Vorobieva
- Department of Biochemistry , University of Cambridge , Cambridge CB2 1GA , United Kingdom
| | - Celine Dutruel
- Department of Biochemistry , University of Cambridge , Cambridge CB2 1GA , United Kingdom
| | - Marko Hyvönen
- Department of Biochemistry , University of Cambridge , Cambridge CB2 1GA , United Kingdom
| | - Florian Hollfelder
- Department of Biochemistry , University of Cambridge , Cambridge CB2 1GA , United Kingdom
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Evolutionary repurposing of a sulfatase: A new Michaelis complex leads to efficient transition state charge offset. Proc Natl Acad Sci U S A 2018; 115:E7293-E7302. [PMID: 30012610 DOI: 10.1073/pnas.1607817115] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The recruitment and evolutionary optimization of promiscuous enzymes is key to the rapid adaptation of organisms to changing environments. Our understanding of the precise mechanisms underlying enzyme repurposing is, however, limited: What are the active-site features that enable the molecular recognition of multiple substrates with contrasting catalytic requirements? To gain insights into the molecular determinants of adaptation in promiscuous enzymes, we performed the laboratory evolution of an arylsulfatase to improve its initially weak phenylphosphonate hydrolase activity. The evolutionary trajectory led to a 100,000-fold enhancement of phenylphosphonate hydrolysis, while the native sulfate and promiscuous phosphate mono- and diester hydrolyses were only marginally affected (≤50-fold). Structural, kinetic, and in silico characterizations of the evolutionary intermediates revealed that two key mutations, T50A and M72V, locally reshaped the active site, improving access to the catalytic machinery for the phosphonate. Measured transition state (TS) charge changes along the trajectory suggest the creation of a new Michaelis complex (E•S, enzyme-substrate), with enhanced leaving group stabilization in the TS for the promiscuous phosphonate (βleavinggroup from -1.08 to -0.42). Rather than altering the catalytic machinery, evolutionary repurposing was achieved by fine-tuning the molecular recognition of the phosphonate in the Michaelis complex, and by extension, also in the TS. This molecular scenario constitutes a mechanistic alternative to adaptation solely based on enzyme flexibility and conformational selection. Instead, rapid functional transitions between distinct chemical reactions rely on the high reactivity of permissive active-site architectures that allow multiple substrate binding modes.
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Theoretical Studies on Catalysis Mechanisms of Serum Paraoxonase 1 and Phosphotriesterase Diisopropyl Fluorophosphatase Suggest the Alteration of Substrate Preference from Paraoxonase to DFP. Molecules 2018; 23:molecules23071660. [PMID: 29986514 PMCID: PMC6100192 DOI: 10.3390/molecules23071660] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Revised: 07/04/2018] [Accepted: 07/05/2018] [Indexed: 12/18/2022] Open
Abstract
The calcium-dependent β-propeller proteins mammalian serum paraoxonase 1 (PON1) and phosphotriesterase diisopropyl fluorophosphatase (DFPase) catalyze the hydrolysis of organophosphorus compounds and enhance hydrolysis of various nerve agents. In the present work, the phosphotriesterase activity development between PON1 and DFPase was investigated by using the hybrid density functional theory method B3LYP. Based on the active-site difference between PON1 and DFPase, both the wild type and the mutant (a water molecule replacing Asn270 in PON1) models were designed. The results indicated that the substitution of a water molecule for Asn270 in PON1 had little effect on the enzyme activity in kinetics, while being more efficient in thermodynamics, which is essential for DFP hydrolysis. Structure comparisons of evolutionarily related enzymes show that the mutation of Asn270 leads to the catalytic Ca2+ ion indirectly connecting the buried structural Ca2+ ion via hydrogen bonds in DFPase. It can reduce the plasticity of enzymatic structure, and possibly change the substrate preference from paraoxon to DFP, which implies an evolutionary transition from mono- to dinuclear catalytic centers. Our studies shed light on the investigation of enzyme catalysis mechanism from an evolutionary perspective.
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Zhang H, Yang L, Ding W, Ma Y. Theoretical Studies on the Catalytic Cycle of Histidine Acid Phosphatases Revealing an Acid Proof Mechanism. J Phys Chem B 2018; 122:7530-7538. [DOI: 10.1021/acs.jpcb.8b04808] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hao Zhang
- College of Life Science and Engineering, Northwest Minzu University, Lanzhou 730030, P. R. China
| | - Ling Yang
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China
| | - Wanjian Ding
- College of Chemistry, Beijing Normal University, Beijing 100086, P. R. China
| | - Yingying Ma
- Institute of Mining Technology, Inner Mongolia University of Technology. Hohhot 010051, P. R. China
- Inner Mongolia Key Laboratory of Theoretical and Computational Chemistry Simulation. Hohhot 010051, P. R. China
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28
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Petrović D, Szeler K, Kamerlin SCL. Challenges and advances in the computational modeling of biological phosphate hydrolysis. Chem Commun (Camb) 2018; 54:3077-3089. [PMID: 29412205 DOI: 10.1039/c7cc09504j] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Phosphate ester hydrolysis is fundamental to many life processes, and has been the topic of substantial experimental and computational research effort. However, even the simplest of phosphate esters can be hydrolyzed through multiple possible pathways that can be difficult to distinguish between, either experimentally, or computationally. Therefore, the mechanisms of both the enzymatic and non-enzymatic reactions have been historically controversial. In the present contribution, we highlight a number of technical issues involved in reliably modeling these computationally challenging reactions, as well as proposing potential solutions. We also showcase examples of our own work in this area, discussing both the non-enzymatic reaction in aqueous solution, as well as insights obtained from the computational modeling of organophosphate hydrolysis and catalytic promiscuity amongst enzymes that catalyze phosphoryl transfer.
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Affiliation(s)
- Dušan Petrović
- Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, S-751 24 Uppsala, Sweden.
| | - Klaudia Szeler
- Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, S-751 24 Uppsala, Sweden.
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29
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Sunden F, AlSadhan I, Lyubimov A, Doukov T, Swan J, Herschlag D. Differential catalytic promiscuity of the alkaline phosphatase superfamily bimetallo core reveals mechanistic features underlying enzyme evolution. J Biol Chem 2017; 292:20960-20974. [PMID: 29070681 DOI: 10.1074/jbc.m117.788240] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 10/19/2017] [Indexed: 11/06/2022] Open
Abstract
Members of enzyme superfamilies specialize in different reactions but often exhibit catalytic promiscuity for one another's reactions, consistent with catalytic promiscuity as an important driver in the evolution of new enzymes. Wanting to understand how catalytic promiscuity and other factors may influence evolution across a superfamily, we turned to the well-studied alkaline phosphatase (AP) superfamily, comparing three of its members, two evolutionarily distinct phosphatases and a phosphodiesterase. We mutated distinguishing active-site residues to generate enzymes that had a common Zn2+ bimetallo core but little sequence similarity and different auxiliary domains. We then tested the catalytic capabilities of these pruned enzymes with a series of substrates. A substantial rate enhancement of ∼1011-fold for both phosphate mono- and diester hydrolysis by each enzyme indicated that the Zn2+ bimetallo core is an effective mono/di-esterase generalist and that the bimetallo cores were not evolutionarily tuned to prefer their cognate reactions. In contrast, our pruned enzymes were ineffective sulfatases, and this limited promiscuity may have provided a driving force for founding the distinct one-metal-ion branch that contains all known AP superfamily sulfatases. Finally, our pruned enzymes exhibited 107-108-fold phosphotriesterase rate enhancements, despite absence of such enzymes within the AP superfamily. We speculate that the superfamily active-site architecture involved in nucleophile positioning prevents accommodation of the additional triester substituent. Overall, we suggest that catalytic promiscuity, and the ease or difficulty of remodeling and building onto existing protein scaffolds, have greatly influenced the course of enzyme evolution. Uncovering principles and properties of enzyme function, promiscuity, and repurposing provides lessons for engineering new enzymes.
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Affiliation(s)
- Fanny Sunden
- From the Department of Biochemistry, Beckman Center
| | | | - Artem Lyubimov
- the Departments of Molecular and Cellular Physiology.,Neurology and Neurological Science.,Structural Biology, and.,Photon Science.,Howard Hughes Medical Institute
| | - Tzanko Doukov
- the Macromolecular Crystallographic Group, Stanford Synchrotron Radiation Lightsource, National Accelerator Laboratory, Stanford University, Stanford, California 94309
| | - Jeffrey Swan
- From the Department of Biochemistry, Beckman Center
| | - Daniel Herschlag
- From the Department of Biochemistry, Beckman Center, .,the Departments of Chemical Engineering and Chemistry, and.,Stanford ChEM-H (Chemistry, Engineering, and Medicine for Human Health), Stanford University, Stanford, California 94305 and
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30
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Discovery of tetrahydro-ß-carboline derivatives as a new class of phosphodiesterase 4 inhibitors. Med Chem Res 2017. [DOI: 10.1007/s00044-017-2011-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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31
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Chu Y, Williams NH, Hengge AC. Transition States and Control of Substrate Preference in the Promiscuous Phosphatase PP1. Biochemistry 2017; 56:3923-3933. [PMID: 28678475 DOI: 10.1021/acs.biochem.7b00441] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Catalytically promiscuous enzymes are an attractive frontier for biochemistry, because enzyme promiscuities not only plausibly explain enzyme evolution through the mechanism of gene duplication but also could provide an efficient route to changing the catalytic function of proteins by mimicking this evolutionary process. PP1γ is an effectively promiscuous phosphatase for the hydrolysis of both monoanionic and dianionic phosphate ester-based substrates. In addition to its native phosphate monoester substrate, PP1γ catalyzes the hydrolysis of aryl methylphosphonates, fluorophosphate esters, phosphorothioate esters, and phosphodiesters, with second-order rate accelerations that fall within the narrow range of 1011-1013. In contrast to the different transition states in the uncatalyzed hydrolysis reactions of these substrates, PP1γ catalyzes their hydrolysis through similar transition states. PP1γ does not catalyze the hydrolysis of a sulfate ester, which is unexpected. The PP1γ active site is tolerant of variations in the geometry of bound ligands, which permit the effective catalysis even of substrates whose steric requirements may result in perturbations to the positioning of the transferring group, both in the initial enzyme-substrate complex and in the transition state. The conservative mutation of arginine 221 to lysine results in a mutant that is a more effective catalyst toward monoanionic substrates. The surprising conversion of substrate preference lends support to the notion that mutations following gene duplication can result in an altered enzyme with different catalytic capabilities and preferences and may provide a pathway for the evolution of new enzymes.
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Affiliation(s)
- Yuan Chu
- Department of Chemistry and Biochemistry, Utah State University , Logan, Utah 84322-0300, United States
| | - Nicholas H Williams
- Centre for Chemical Biology, Department of Chemistry, University of Sheffield , Sheffield S3 7HF, U.K
| | - Alvan C Hengge
- Department of Chemistry and Biochemistry, Utah State University , Logan, Utah 84322-0300, United States
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