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Xu H, Xu D, Liu Y. Molecular Biology Applications of Psychrophilic Enzymes: Adaptations, Advantages, Expression, and Prospective. Appl Biochem Biotechnol 2024:10.1007/s12010-023-04810-5. [PMID: 38183603 DOI: 10.1007/s12010-023-04810-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2023] [Indexed: 01/08/2024]
Abstract
Psychrophilic enzymes are primarily produced by microorganisms from extremely low-temperature environments which are known as psychrophiles. Their high efficiency at low temperatures and easy heat inactivation property have attracted extensive attention from various food and industrial bioprocesses. However, the application of these enzymes in molecular biology is still limited. In a previous review, the applications of psychrophilic enzymes in industries such as the detergent additives, the food additives, the bioremediation, and the pharmaceutical medicine, and cosmetics have been discussed. In this review, we discuss the main cold adaptation characteristics of psychrophiles and psychrophilic enzymes, as well as the relevant information on different psychrophilic enzymes in molecular biology. We summarize the mining and screening methods of psychrophilic enzymes. We finally recap the expression of psychrophilic enzymes. We aim to provide a reference process for the exploration and expression of new generation of psychrophilic enzymes.
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Affiliation(s)
- Hu Xu
- Center for Pan-Third Pole Environment, Lanzhou University, Lanzhou, 730000, China
- CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing, 100190, China
| | - Dawei Xu
- CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing, 100190, China.
| | - Yongqin Liu
- Center for Pan-Third Pole Environment, Lanzhou University, Lanzhou, 730000, China.
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100101, China.
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2
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Dechkla M, Charoenjotivadhanakul S, Imtong C, Visitsattapongse S, Li HC, Angsuthanasombat C. Cry4Aa and Cry4Ba Mosquito-Active Toxins Utilize Different Domains in Binding to a Particular Culex ALP Isoform: A Functional Toxin Receptor Implicating Differential Actions on Target Larvae. Toxins (Basel) 2022; 14:toxins14100652. [PMID: 36287921 PMCID: PMC9607545 DOI: 10.3390/toxins14100652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/10/2022] [Accepted: 09/16/2022] [Indexed: 11/16/2022] Open
Abstract
The three-domain Cry4Aa toxin produced from Bacillus thuringiensis subsp. israelensis was previously shown to be much more toxic to Culex mosquito larvae than its closely related toxin—Cry4Ba. The interaction of these two individual toxins with target receptors on susceptible larval midgut cells is likely to be the critical determinant in their differential toxicity. Here, two full-length membrane-bound alkaline phosphatase (mALP) isoforms from Culex quinquefasciatus larvae, Cq-mALP1263and Cq-mALP1264, predicted to be GPI-linked was cloned and functionally expressed in Spodoptera frugiperda (Sf9) cells as 57- and 61-kDa membrane-bound proteins, respectively. Bioinformatics analysis disclosed that both Cq-mALP isoforms share significant sequence similarity to Aedes aegypti-mALP—a Cry4Ba toxin receptor. In cytotoxicity assays, Sf9 cells expressing Cq-mALP1264, but not Cq-mALP1263, showed remarkably greater susceptibility to Cry4Aa than Cry4Ba, while immunolocalization studies revealed that both toxins were capable of binding to each Cq-mALP expressed on the cell membrane surface. Molecular docking of the Cq-mALP1264-modeled structure with individual Cry4 toxins revealed that Cry4Aa could bind to Cq-mALP1264 primarily through particular residues on three surface-exposed loops in the receptor-binding domain—DII, including Thr512, Tyr513 and Lys514 in the β10-β11loop. Dissimilarly, Cry4Ba appeared to utilize only certain residues in its C-terminal domain—DIII to interact with such a Culex counterpart receptor. Ala-substitutions of selected β10-β11loop residues (T512A, Y513A and K514A) revealed that only the K514A mutant displayed a drastic decrease in biotoxicity against C. quinquefasciatus larvae. Further substitution of Lys514 with Asp (K514D) revealed a further decrease in larval toxicity. Furthermore, in silico calculation of the binding affinity change (ΔΔGbind) in Cry4Aa-Cq-mALP1264 interactions upon these single-substitutions revealed that the K514D mutation displayed the largest ΔΔGbind value as compared to three other mutations, signifying an adverse impact of a negative charge at this critical receptor-binding position. Altogether, our present study has disclosed that these two related-Cry4 mosquito-active toxins conceivably exploited different domains in functional binding to the same Culex membrane-bound ALP isoform—Cq-mALP1264 for mediating differential toxicity against Culex target larvae.
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Affiliation(s)
- Manussawee Dechkla
- Department of Environmental Biology, Faculty of Science and Technology, Suan Sunandha Rajabhat University, Bangkok 10300, Thailand
- Correspondence: (M.D.); (C.A.)
| | - Sathapat Charoenjotivadhanakul
- Bacterial Toxin Research Innovation Cluster (BRIC), Institute of Molecular Biosciences, Salaya Campus, Mahidol University, Nakorn Pathom 73170, Thailand
| | - Chompounoot Imtong
- Laboratory of Structural Biochemistry and Cell Chemical Biology, Biophysics Institute for Research and Development (BIRD), Fang, Chiang Mai 50110, Thailand
| | - Sarinporn Visitsattapongse
- Department of Biomedical Engineering, School of Engineering, King Mongkut’s Institute of Technology Ladkrabang, Ladkrabang, Bangkok 10520, Thailand
| | - Hui-Chun Li
- Department of Biochemistry, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan
| | - Chanan Angsuthanasombat
- Bacterial Toxin Research Innovation Cluster (BRIC), Institute of Molecular Biosciences, Salaya Campus, Mahidol University, Nakorn Pathom 73170, Thailand
- Laboratory of Structural Biochemistry and Cell Chemical Biology, Biophysics Institute for Research and Development (BIRD), Fang, Chiang Mai 50110, Thailand
- Department of Biochemistry, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan
- Correspondence: (M.D.); (C.A.)
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Ajitha M, Sundar K, Arul Mugilan S, Arumugam S. Development of METAL-ACTIVE SITE and ZINCCLUSTER tool to predict active site pockets. Proteins 2018; 86:322-331. [PMID: 29235146 DOI: 10.1002/prot.25441] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 11/08/2017] [Accepted: 12/10/2017] [Indexed: 12/31/2022]
Abstract
The advent of whole genome sequencing leads to increasing number of proteins with known amino acid sequences. Despite many efforts, the number of proteins with resolved three dimensional structures is still low. One of the challenging tasks the structural biologists face is the prediction of the interaction of metal ion with any protein for which the structure is unknown. Based on the information available in Protein Data Bank, a site (METALACTIVE INTERACTION) has been generated which displays information for significant high preferential and low-preferential combination of endogenous ligands for 49 metal ions. User can also gain information about the residues present in the first and second coordination sphere as it plays a major role in maintaining the structure and function of metalloproteins in biological system. In this paper, a novel computational tool (ZINCCLUSTER) is developed, which can predict the zinc metal binding sites of proteins even if only the primary sequence is known. The purpose of this tool is to predict the active site cluster of an uncharacterized protein based on its primary sequence or a 3D structure. The tool can predict amino acids interacting with a metal or vice versa. This tool is based on the occurrence of significant triplets and it is tested to have higher prediction accuracy when compared to that of other available techniques.
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Affiliation(s)
- M Ajitha
- Kalasalingam University, Krishnankoil, Tamil Nadu, India
| | - K Sundar
- Kalasalingam University, Krishnankoil, Tamil Nadu, India
| | - S Arul Mugilan
- Raja Doraisingam Government Arts College, Sivaganga, Tamil Nadu, India
| | - S Arumugam
- Kalasalingam University, Krishnankoil, Tamil Nadu, India
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Barrozo A, Duarte F, Bauer P, Carvalho ATP, Kamerlin SCL. Cooperative Electrostatic Interactions Drive Functional Evolution in the Alkaline Phosphatase Superfamily. J Am Chem Soc 2015; 137:9061-76. [PMID: 26091851 PMCID: PMC4513756 DOI: 10.1021/jacs.5b03945] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
It is becoming widely accepted that catalytic promiscuity, i.e., the ability of a single enzyme to catalyze the turnover of multiple, chemically distinct substrates, plays a key role in the evolution of new enzyme functions. In this context, the members of the alkaline phosphatase superfamily have been extensively studied as model systems in order to understand the phenomenon of enzyme multifunctionality. In the present work, we model the selectivity of two multiply promiscuous members of this superfamily, namely the phosphonate monoester hydrolases from Burkholderia caryophylli and Rhizobium leguminosarum. We have performed extensive simulations of the enzymatic reaction of both wild-type enzymes and several experimentally characterized mutants. Our computational models are in agreement with key experimental observables, such as the observed activities of the wild-type enzymes, qualitative interpretations of experimental pH-rate profiles, and activity trends among several active site mutants. In all cases the substrates of interest bind to the enzyme in similar conformations, with largely unperturbed transition states from their corresponding analogues in aqueous solution. Examination of transition-state geometries and the contribution of individual residues to the calculated activation barriers suggest that the broad promiscuity of these enzymes arises from cooperative electrostatic interactions in the active site, allowing each enzyme to adapt to the electrostatic needs of different substrates. By comparing the structural and electrostatic features of several alkaline phosphatases, we suggest that this phenomenon is a generalized feature driving selectivity and promiscuity within this superfamily and can be in turn used for artificial enzyme design.
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Affiliation(s)
- Alexandre Barrozo
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, SE-751 24, Uppsala, Sweden
| | - Fernanda Duarte
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, SE-751 24, Uppsala, Sweden
| | - Paul Bauer
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, SE-751 24, Uppsala, Sweden
| | - Alexandra T P Carvalho
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, SE-751 24, Uppsala, Sweden
| | - Shina C L Kamerlin
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, BMC Box 596, SE-751 24, Uppsala, Sweden
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Arai S, Yonezawa Y, Ishibashi M, Matsumoto F, Adachi M, Tamada T, Tokunaga H, Blaber M, Tokunaga M, Kuroki R. Structural characteristics of alkaline phosphatase from the moderately halophilic bacterium Halomonas sp. 593. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:811-20. [PMID: 24598750 PMCID: PMC3949524 DOI: 10.1107/s1399004713033609] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 12/11/2013] [Indexed: 11/24/2022]
Abstract
Alkaline phosphatase (AP) from the moderate halophilic bacterium Halomonas sp. 593 (HaAP) catalyzes the hydrolysis of phosphomonoesters over a wide salt-concentration range (1-4 M NaCl). In order to clarify the structural basis of its halophilic characteristics and its wide-range adaptation to salt concentration, the tertiary structure of HaAP was determined by X-ray crystallography to 2.1 Å resolution. The unit cell of HaAP contained one dimer unit corresponding to the biological unit. The monomer structure of HaAP contains a domain comprised of an 11-stranded β-sheet core with 19 surrounding α-helices similar to those of APs from other species, and a unique `crown' domain containing an extended `arm' structure that participates in formation of a hydrophobic cluster at the entrance to the substrate-binding site. The HaAP structure also displays a unique distribution of negatively charged residues and hydrophobic residues in comparison to other known AP structures. AP from Vibrio sp. G15-21 (VAP; a slight halophile) has the highest similarity in sequence (70.0% identity) and structure (C(α) r.m.s.d. of 0.82 Å for the monomer) to HaAP. The surface of the HaAP dimer is substantially more acidic than that of the VAP dimer (144 exposed Asp/Glu residues versus 114, respectively), and thus may enable the solubility of HaAP under high-salt conditions. Conversely, the monomer unit of HaAP formed a substantially larger hydrophobic interior comprising 329 C atoms from completely buried residues, whereas that of VAP comprised 264 C atoms, which may maintain the stability of HaAP under low-salt conditions. These characteristics of HaAP may be responsible for its unique functional adaptation permitting activity over a wide range of salt concentrations.
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Affiliation(s)
- Shigeki Arai
- Quantum Beam Science Directorate, Japan Atomic Energy Agency, 2-4 Shirakata-shirane, Tokai, Ibaraki 319-1195, Japan
| | - Yasushi Yonezawa
- Quantum Beam Science Directorate, Japan Atomic Energy Agency, 2-4 Shirakata-shirane, Tokai, Ibaraki 319-1195, Japan
| | - Matsujiro Ishibashi
- Applied and Molecular Microbiology, Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Fumiko Matsumoto
- Quantum Beam Science Directorate, Japan Atomic Energy Agency, 2-4 Shirakata-shirane, Tokai, Ibaraki 319-1195, Japan
| | - Motoyasu Adachi
- Quantum Beam Science Directorate, Japan Atomic Energy Agency, 2-4 Shirakata-shirane, Tokai, Ibaraki 319-1195, Japan
| | - Taro Tamada
- Quantum Beam Science Directorate, Japan Atomic Energy Agency, 2-4 Shirakata-shirane, Tokai, Ibaraki 319-1195, Japan
| | - Hiroko Tokunaga
- Applied and Molecular Microbiology, Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Michael Blaber
- College of Medicine, Florida State University, 1115 West Call Street, Tallahassee, FL 32306-4300, USA
| | - Masao Tokunaga
- Applied and Molecular Microbiology, Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Ryota Kuroki
- Quantum Beam Science Directorate, Japan Atomic Energy Agency, 2-4 Shirakata-shirane, Tokai, Ibaraki 319-1195, Japan
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6
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Rosta E, Yang W, Hummer G. Calcium inhibition of ribonuclease H1 two-metal ion catalysis. J Am Chem Soc 2014; 136:3137-44. [PMID: 24499076 PMCID: PMC3985467 DOI: 10.1021/ja411408x] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Indexed: 01/05/2023]
Abstract
Most phosphate-processing enzymes require Mg(2+) as a cofactor to catalyze nucleotide cleavage and transfer reactions. Ca(2+) ions inhibit many of these enzymatic activities, despite Ca(2+) and Mg(2+) having comparable binding affinities and overall biological abundances. Here we study the molecular details of the calcium inhibition mechanism for phosphodiester cleavage, an essential reaction in the metabolism of nucleic acids and nucleotides, by comparing Ca(2+)- and Mg(2+) catalyzed reactions. We study the functional roles of the specific metal ion sites A and B in enabling the catalytic cleavage of an RNA/DNA hybrid substrate by B. halodurans ribonuclease (RNase) H1 using hybrid quantum-mechanics/molecular mechanics (QM/MM) free energy calculations. We find that Ca(2+) substitution of either of the two active-site Mg(2+) ions substantially increases the height of the reaction barrier and thereby abolishes the catalytic activity. Remarkably, Ca(2+) at the A site is inactive also in Mg(2+)-optimized active-site structures along the reaction path, whereas Mg(2+) substitution recovers activity in Ca(2+)-optimized structures. Geometric changes resulting from Ca(2+) substitution at metal ion site A may thus be a secondary factor in the loss of catalytic activity. By contrast, at metal ion site B geometry plays a more important role, with only a partial recovery of activity after Mg(2+) substitution in Ca(2+)-optimized structures. Ca(2+)-substitution also leads to a change in mechanism, with deprotonation of the water nucleophile requiring a closer approach to the scissile phosphate, which in turn increases the barrier. As a result, Ca(2+) is less efficient in activating the water. As a likely cause for the different reactivities of Mg(2+) and Ca(2+) ions in site A, we identify differences in charge transfer to the ions and the associated decrease in the pKa of the oxygen nucleophile attacking the phosphate group.
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Affiliation(s)
- Edina Rosta
- Laboratory
of Chemical Physics, National Institute of
Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
- Department
of Chemistry, King’s College London, London SE1 1DB, United Kingdom
| | - Wei Yang
- Laboratory
of Molecular Biology, National Institute
of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Gerhard Hummer
- Laboratory
of Chemical Physics, National Institute of
Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
- Department
of Theoretical Biophysics, Max Planck Institute
of Biophysics, 60438 Frankfurt am Main, Germany
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Chakraborty S, Ásgeirsson B, Rao BJ. A measure of the broad substrate specificity of enzymes based on 'duplicate' catalytic residues. PLoS One 2012; 7:e49313. [PMID: 23166637 PMCID: PMC3500292 DOI: 10.1371/journal.pone.0049313] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 10/08/2012] [Indexed: 11/18/2022] Open
Abstract
The ability of an enzyme to select and act upon a specific class of compounds with unerring precision and efficiency is an essential feature of life. Simultaneously, these enzymes often catalyze the reaction of a range of similar substrates of the same class, and also have promiscuous activities on unrelated substrates. Previously, we have established a methodology to quantify promiscuous activities in a wide range of proteins. In the current work, we quantitatively characterize the active site for the ability to catalyze distinct, yet related, substrates (BRASS). A protein with known structure and active site residues provides the framework for computing ‘duplicate’ residues, each of which results in slightly modified replicas of the active site scaffold. Such spatial congruence is supplemented by Finite difference Poisson Boltzmann analysis which filters out electrostatically unfavorable configurations. The congruent configurations are used to compute an index (BrassIndex), which reflects the broad substrate profile of the active site. We identify an acetylhydrolase and a methyltransferase as having the lowest and highest BrassIndex, respectively, from a set of non-homologous proteins extracted from the Catalytic Site Atlas. The acetylhydrolase, a regulatory enzyme, is known to be highly specific for platelet-activating factor. In the methyltransferase (PDB: 1QAM), various combinations of glycine (Gly38/40/42), asparagine (Asn101/11) and glutamic acid (Glu59/36) residues having similar spatial and electrostatic profiles with the specified scaffold (Gly38, Asn101 and Glu59) exemplifies the broad substrate profile such an active site may provide. ‘Duplicate’ residues identified by relaxing the spatial and/or electrostatic constraints can be the target of directed evolution methodologies, like saturation mutagenesis, for modulating the substrate specificity of proteins.
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Affiliation(s)
- Sandeep Chakraborty
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India.
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Chakraborty S, Asgeirsson B, Minda R, Salaye L, Frère JM, Rao BJ. Inhibition of a cold-active alkaline phosphatase by imipenem revealed by in silico
modeling of metallo-β-lactamase active sites. FEBS Lett 2012; 586:3710-5. [PMID: 22982109 DOI: 10.1016/j.febslet.2012.08.030] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 08/24/2012] [Accepted: 08/24/2012] [Indexed: 11/30/2022]
Affiliation(s)
- Sandeep Chakraborty
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India.
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Igunnu A, Osalaye DS, Olorunsogo OO, Malomo SO, Olorunniji FJ. Distinct metal ion requirements for the phosphomonoesterase and phosphodiesterase activities of calf intestinal alkaline phosphatase. Open Biochem J 2011; 5:67-72. [PMID: 22262982 PMCID: PMC3258565 DOI: 10.2174/1874091x01105010067] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 10/28/2011] [Accepted: 10/30/2011] [Indexed: 11/22/2022] Open
Abstract
The roles of Mg2+ and Zn2+ ions in promoting phosphoryl transfer catalysed by alkaline phosphatase are yet to be fully characterised. We investigated the divalent metal ion requirements for the monoesterase and diesterase activities of calf intestinal alkaline phosphatase. The synergistic effect of Mg2+ and Zn2+ in promoting the hydrolysis of para-nitrophenyl phosphate (monoesterase reaction) by alkaline phosphatase is not observed in the hydrolysis of the diesterase substrate, bis-para-nitrophenyl phosphate. Indeed, the diesterase reaction is inhibited by concentrations of Mg2+ that were optimal for the monoesterase reaction. This study reveals that the substrate specificities of alkaline phosphatases and related bimetalloenzymes are subject to regulation by changes in the nature and availability of cofactors, and the different cofactor requirements of the monoesterase and diesterase reactions of mammalian alkaline phosphatases could have significance for the biological functions of the enzymes.
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Affiliation(s)
- Adedoyin Igunnu
- Department of Biochemistry, Faculty of Science, University of Ilorin, Ilorin, Nigeria
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Chakraborty S, Minda R, Salaye L, Bhattacharjee SK, Rao BJ. Active site detection by spatial conformity and electrostatic analysis--unravelling a proteolytic function in shrimp alkaline phosphatase. PLoS One 2011; 6:e28470. [PMID: 22174814 PMCID: PMC3234256 DOI: 10.1371/journal.pone.0028470] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 11/08/2011] [Indexed: 11/30/2022] Open
Abstract
Computational methods are increasingly gaining importance as an aid in identifying active sites. Mostly these methods tend to have structural information that supplement sequence conservation based analyses. Development of tools that compute electrostatic potentials has further improved our ability to better characterize the active site residues in proteins. We have described a computational methodology for detecting active sites based on structural and electrostatic conformity - CataLytic Active Site Prediction (CLASP). In our pipelined model, physical 3D signature of any particular enzymatic function as defined by its active sites is used to obtain spatially congruent matches. While previous work has revealed that catalytic residues have large pKa deviations from standard values, we show that for a given enzymatic activity, electrostatic potential difference (PD) between analogous residue pairs in an active site taken from different proteins of the same family are similar. False positives in spatially congruent matches are further pruned by PD analysis where cognate pairs with large deviations are rejected. We first present the results of active site prediction by CLASP for two enzymatic activities - β-lactamases and serine proteases, two of the most extensively investigated enzymes. The results of CLASP analysis on motifs extracted from Catalytic Site Atlas (CSA) are also presented in order to demonstrate its ability to accurately classify any protein, putative or otherwise, with known structure. The source code and database is made available at www.sanchak.com/clasp/. Subsequently, we probed alkaline phosphatases (AP), one of the well known promiscuous enzymes, for additional activities. Such a search has led us to predict a hitherto unknown function of shrimp alkaline phosphatase (SAP), where the protein acts as a protease. Finally, we present experimental evidence of the prediction by CLASP by showing that SAP indeed has protease activity in vitro.
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Affiliation(s)
- Sandeep Chakraborty
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
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11
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Dupureur CM. One is enough: insights into the two-metal ion nuclease mechanism from global analysis and computational studies. Metallomics 2010; 2:609-20. [PMID: 21072352 DOI: 10.1039/c0mt00013b] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Cynthia M Dupureur
- Department of Chemistry & Biochemistry and The Center for Nanoscience, University of Missouri-St. Louis, One University Blvd., St. Louis, MO 63121, USA.
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