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1.
Int J Mol Sci ; 25(9)2024 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-38732240

RESUMEN

Methicillin-resistant Staphylococcus aureus (MRSA) infection has rapidly spread through various routes. A genomic analysis of clinical MRSA samples revealed an unknown protein, Sav2152, predicted to be a haloacid dehalogenase (HAD)-like hydrolase, making it a potential candidate for a novel drug target. In this study, we determined the crystal structure of Sav2152, which consists of a C2-type cap domain and a core domain. The core domain contains four motifs involved in phosphatase activity that depend on the presence of Mg2+ ions. Specifically, residues D10, D12, and D233, which closely correspond to key residues in structurally homolog proteins, are responsible for binding to the metal ion and are known to play critical roles in phosphatase activity. Our findings indicate that the Mg2+ ion known to stabilize local regions surrounding it, however, paradoxically, destabilizes the local region. Through mutant screening, we identified D10 and D12 as crucial residues for metal binding and maintaining structural stability via various uncharacterized intra-protein interactions, respectively. Substituting D10 with Ala effectively prevents the interaction with Mg2+ ions. The mutation of D12 disrupts important structural associations mediated by D12, leading to a decrease in the stability of Sav2152 and an enhancement in binding affinity to Mg2+ ions. Additionally, our study revealed that D237 can replace D12 and retain phosphatase activity. In summary, our work uncovers the novel role of metal ions in HAD-like phosphatase activity.


Asunto(s)
Proteínas Bacterianas , Hidrolasas , Magnesio , Monoéster Fosfórico Hidrolasas , Magnesio/metabolismo , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Monoéster Fosfórico Hidrolasas/metabolismo , Monoéster Fosfórico Hidrolasas/química , Monoéster Fosfórico Hidrolasas/genética , Hidrolasas/metabolismo , Hidrolasas/química , Hidrolasas/genética , Modelos Moleculares , Staphylococcus aureus Resistente a Meticilina/enzimología , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus/enzimología , Cristalografía por Rayos X , Unión Proteica
2.
J Gen Physiol ; 156(7)2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38771271

RESUMEN

The voltage-sensing domain (VSD) is a four-helix modular protein domain that converts electrical signals into conformational changes, leading to open pores and active enzymes. In most voltage-sensing proteins, the VSDs do not interact with one another, and the S1-S3 helices are considered mainly scaffolding, except in the voltage-sensing phosphatase (VSP) and the proton channel (Hv). To investigate its contribution to VSP function, we mutated four hydrophobic amino acids in S1 to alanine (F127, I131, I134, and L137), individually or in combination. Most of these mutations shifted the voltage dependence of activity to higher voltages; however, not all substrate reactions were the same. The kinetics of enzymatic activity were also altered, with some mutations significantly slowing down dephosphorylation. The voltage dependence of VSD motions was consistently shifted to lower voltages and indicated a second voltage-dependent motion. Additionally, none of the mutations broke the VSP dimer, indicating that the S1 impact could stem from intra- and/or intersubunit interactions. Lastly, when the same mutations were introduced into a genetically encoded voltage indicator, they dramatically altered the optical readings, making some of the kinetics faster and shifting the voltage dependence. These results indicate that the S1 helix in VSP plays a critical role in tuning the enzyme's conformational response to membrane potential transients and influencing the function of the VSD.


Asunto(s)
Monoéster Fosfórico Hidrolasas , Animales , Monoéster Fosfórico Hidrolasas/metabolismo , Monoéster Fosfórico Hidrolasas/genética , Monoéster Fosfórico Hidrolasas/química , Interacciones Hidrofóbicas e Hidrofílicas , Mutación , Dominios Proteicos , Cinética , Humanos , Fosforilación
3.
Protein Sci ; 33(6): e5009, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38747379

RESUMEN

PHPT1 is a histidine phosphatase that modulates signaling in eukaryotes through its catalytic activity. Here, we present an analysis of the structure and dynamics of PHPT1 through a combination of solution NMR, molecular dynamics, and biochemical experiments. We identify a salt bridge formed between the R78 guanidinium moiety and the C-terminal carboxyl group on Y125 that is critical for ligand binding. Disruption of the salt bridge by appending a glycine residue at the C-terminus (G126) leads to a decrease in catalytic activity and binding affinity for the pseudo substrate, para-nitrophenylphosphate (pNPP), as well as the active site inhibitor, phenylphosphonic acid (PPA). We show through NMR chemical shift, 15N relaxation measurements, and analysis of molecular dynamics trajectories, that removal of this salt bridge results in an active site that is altered both structurally and dynamically thereby significantly impacting enzymatic function and confirming the importance of this electrostatic interaction.


Asunto(s)
Dominio Catalítico , Simulación de Dinámica Molecular , Especificidad por Sustrato , Resonancia Magnética Nuclear Biomolecular , Monoéster Fosfórico Hidrolasas/química , Monoéster Fosfórico Hidrolasas/metabolismo , Humanos
4.
Acta Physiol (Oxf) ; 240(5): e14137, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38502065

RESUMEN

BACKGROUND: Voltage-sensing phosphatase contains a structurally conserved S1-S4-based voltage-sensor domain, which undergoes a conformational transition in response to membrane potential change. Unlike that of channels, it is functional even in isolation and is therefore advantageous for studying the transition mechanism, but its nature has not yet been fully elucidated. This study aimed to address whether the cytoplasmic N-terminus and S1 exhibit structural change. METHODS: Anap, an environment-sensitive unnatural fluorescent amino acid, was site-specifically introduced to the voltage sensor domain to probe local structural changes by using oocyte voltage clamp and photometry. Tetramethylrhodamine was also used to probe some extracellularly accessible positions. In total, 51 positions were investigated. RESULTS: We detected robust voltage-dependent signals from widely distributed positions including N-terminus and S1. In addition, response to hyperpolarization was observed at the extracellular end of S1, reflecting the local structure flexibility of the voltage-sensor domain in the down-state. We also found that the mechanical coupling between the voltage-sensor and phosphatase domains affects the depolarization-induced optical signals but not the hyperpolarization-induced signals. CONCLUSIONS: These results fill a gap between the previous interpretations from the structural and biophysical approaches and should provide important insights into the mechanisms of the voltage-sensor domain transition as well as its coupling with the effector.


Asunto(s)
Potenciales de la Membrana , Animales , Potenciales de la Membrana/fisiología , Oocitos/metabolismo , Monoéster Fosfórico Hidrolasas/metabolismo , Monoéster Fosfórico Hidrolasas/química , Monoéster Fosfórico Hidrolasas/genética , Citoplasma/metabolismo , Xenopus laevis , Dominios Proteicos , Técnicas de Placa-Clamp
5.
Structure ; 32(4): 453-466.e6, 2024 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-38309262

RESUMEN

SHIP1, an inositol 5-phosphatase, plays a central role in cellular signaling. As such, it has been implicated in many conditions. Exploiting SHIP1 as a drug target will require structural knowledge and the design of selective small molecules. We have determined apo, and magnesium and phosphate-bound structures of the phosphatase and C2 domains of SHIP1. The C2 domains of SHIP1 and the related SHIP2 modulate the activity of the phosphatase domain. To understand the mechanism, we performed activity assays, hydrogen-deuterium exchange mass spectrometry, and molecular dynamics on SHIP1 and SHIP2. Our findings demonstrate that the influence of the C2 domain is more pronounced for SHIP2 than SHIP1. We determined 91 structures of SHIP1 with fragments bound, with some near the interface between the two domains. We performed a mass spectrometry screen and determined four structures with covalent fragments. These structures could act as starting points for the development of potent, selective probes.


Asunto(s)
Dominios C2 , Monoéster Fosfórico Hidrolasas , Inositol Polifosfato 5-Fosfatasas/metabolismo , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatasas/genética , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatasas/metabolismo , Monoéster Fosfórico Hidrolasas/genética , Monoéster Fosfórico Hidrolasas/química , Monoéster Fosfórico Hidrolasas/metabolismo , Humanos
6.
J Med Chem ; 67(3): 1949-1960, 2024 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-38252624

RESUMEN

The suppressor of T cell receptor signaling (Sts) proteins are negative regulators of immune signaling. Genetic inactivation of these proteins leads to significant resistance to infection. From a 590,000 compound high-throughput screen, we identified the 2-(1H)-quinolinone derivative, rebamipide, as a putative inhibitor of Sts phosphatase activity. Rebamipide, and a small library of derivatives, are competitive, selective inhibitors of Sts-1 with IC50 values from low to submicromolar. SAR analysis indicates that the quinolinone, the acid, and the amide moieties are all essential for activity. A crystal structure confirmed the SAR and reveals key interactions between this class of compound and the protein. Although rebamipide has poor cell permeability, we demonstrated that a liposomal preparation can inactivate the phosphatase activity of Sts-1 in cells. These studies demonstrate that Sts-1 enzyme activity can be pharmacologically inactivated and provide foundational tools and insights for the development of immune-enhancing therapies that target the Sts proteins.


Asunto(s)
Alanina/análogos & derivados , Histidina , Quinolonas , Receptores de Antígenos de Linfocitos T , Quinolonas/farmacología , Monoéster Fosfórico Hidrolasas/química , Inhibidores Enzimáticos
7.
Proteins ; 92(1): 96-105, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37646471

RESUMEN

Methyl parathion hydrolase (MPH) is an enzyme of the metallo-ß-lactamase superfamily, which hydrolyses a wide range of organophosphates (OPs). Recently, MPH has attracted attention as a promising enzymatic bioremediator. The crystal structure of MPH enzyme shows a dimeric form, with each subunit containing a binuclear metal ion center. MPH also demonstrates metal ion-dependent selectivity patterns. The origins of these patterns remain unclear but are linked to open questions about the more general role of metal ions in functional evolution and divergence within enzyme superfamilies. We aimed to investigate and compare the binding of different OP pesticides to MPH with cobalt(II) metal ions. In this study, MPH was modeled from Ochrobactrum sp. with different OP pesticides bound, including methyl paraoxon and dichlorvos and profenofos. The docked structures for each substrate optimized by DFT calculation were selected and subjected to atomistic molecular dynamics simulations for 500 ns. It was found that alpha metal ions did not coordinate with all the pesticides. Rather, the pesticides coordinated with less buried beta metal ions. It was also observed that the coordination of beta metal ions was perturbed to accommodate the pesticides. The binding free energy calculations and structure-based pharmacophore model revealed that all the three substrates could bind well at the active site. However, profenofos exhibit a stronger binding affinity to MPH in comparison to the other two substrates. Therefore, our findings provide molecular insight on the binding of different OP pesticides which could help us design the enzyme for OP pesticides degradation.


Asunto(s)
Metil Paratión , Ochrobactrum , Plaguicidas , Metil Paratión/metabolismo , Organofosfatos/química , Organofosfatos/metabolismo , Hidrolasas , Ochrobactrum/metabolismo , Monoéster Fosfórico Hidrolasas/química , Monoéster Fosfórico Hidrolasas/metabolismo , Metales/química , Iones
8.
ChemMedChem ; 18(15): e202300187, 2023 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-37267298

RESUMEN

PHPT1 is a protein histidine phosphatase that has been implicated in several disease pathways, but the chemical tools necessary to study the biological roles of this enzyme and investigate its utility as a therapeutic target have yet to be developed. To this end, the discovery of PHPT1 inhibitors is an area of significant interest. Here, we report an investigation of illudalic acid and illudalic acid analog-based inhibition of PHPT1 activity. Four of the seven analogs investigated had IC50 values below 5 µM, with the most potent compound (IA1-8H2) exhibiting an IC50 value of 3.4±0.7 µM. Interestingly, these compounds appear to be non-covalent, non-competitive inhibitors of PHPT1 activity, in contrast to other recently reported PHPT1 inhibitors. Mutating the three cysteine residues to alanine has no effect on inhibition, indicating that cysteine is not critical for interactions between inhibitor and enzyme.


Asunto(s)
Productos Biológicos , Histidina , Productos Biológicos/farmacología , Cisteína , Monoéster Fosfórico Hidrolasas/química , Monoéster Fosfórico Hidrolasas/metabolismo
9.
Biomolecules ; 13(4)2023 03 29.
Artículo en Inglés | MEDLINE | ID: mdl-37189363

RESUMEN

Lowe Syndrome (LS) is a condition due to mutations in the OCRL1 gene, characterized by congenital cataracts, intellectual disability, and kidney malfunction. Unfortunately, patients succumb to renal failure after adolescence. This study is centered in investigating the biochemical and phenotypic impact of patient's OCRL1 variants (OCRL1VAR). Specifically, we tested the hypothesis that some OCRL1VAR are stabilized in a non-functional conformation by focusing on missense mutations affecting the phosphatase domain, but not changing residues involved in binding/catalysis. The pathogenic and conformational characteristics of the selected variants were evaluated in silico and our results revealed some OCRL1VAR to be benign, while others are pathogenic. Then we proceeded to monitor the enzymatic activity and function in kidney cells of the different OCRL1VAR. Based on their enzymatic activity and presence/absence of phenotypes, the variants segregated into two categories that also correlated with the severity of the condition they induce. Overall, these two groups mapped to opposite sides of the phosphatase domain. In summary, our findings highlight that not every mutation affecting the catalytic domain impairs OCRL1's enzymatic activity. Importantly, data support the inactive-conformation hypothesis. Finally, our results contribute to establishing the molecular and structural basis for the observed heterogeneity in severity/symptomatology displayed by patients.


Asunto(s)
Síndrome Oculocerebrorrenal , Humanos , Síndrome Oculocerebrorrenal/genética , Monoéster Fosfórico Hidrolasas/genética , Monoéster Fosfórico Hidrolasas/química , Mutación , Mutación Missense , Fenotipo
10.
FEBS Lett ; 597(13): 1770-1778, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-36914375

RESUMEN

Human MutT homolog 1 (MTH1), also known as Nudix-type motif 1 (NUDT1), hydrolyzes 8-oxo-dGTP and 2-oxo-dATP with broad substrate recognition and has attracted attention in anticancer therapeutics. Previous studies on MTH1 have proposed that the exchange of the protonation state between Asp119 and Asp120 is essential for the broad substrate recognition of MTH1. To understand the relationship between protonation states and substrate binding, we determined the crystal structures of MTH1 at pH 7.7-9.7. With increasing pH, MTH1 gradually loses its substrate-binding ability, indicating that Asp119 is deprotonated at pH 8.0-9.1 in 8-oxo-dGTP recognition and Asp120 is deprotonated at pH 8.6-9.7 in 2-oxo-dATP recognition. These results confirm that MTH1 recognizes 8-oxo-dGTP and 2-oxo-dATP by exchanging the protonation state between Asp119 and Asp120 with higher pKa .


Asunto(s)
Monoéster Fosfórico Hidrolasas , Pirofosfatasas , Humanos , Pirofosfatasas/química , Pirofosfatasas/metabolismo , Monoéster Fosfórico Hidrolasas/química , Enzimas Reparadoras del ADN/química , Enzimas Reparadoras del ADN/metabolismo , Hidrolasas Nudix
11.
J Biomol Struct Dyn ; 41(23): 14036-14048, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36762717

RESUMEN

Bipolar disorder is a major psychiatric disorder associated with cognitive impairment and a high suicide rate. Frontline therapy for this condition includes lithium (Li+)-containing treatments that can exert severe side effects. One target of Li+ is inositol monophosphatase-1 (IMPase1); inhibition of IMPase1 through small-molecule compounds may provide an alternative treatment for bipolar disorder. One such compound is the anti-inflammatory drug ebselen, which is well tolerated and safe; however, ebselen's exact mechanism of action in IMPase1 inhibition is not fully understood, preventing rational design of IMPase1 inhibitors. To fill this gap, we performed crystallographic and biochemical studies to investigate how ebselen inhibits IMPase1. We obtained a structure of IMPase1 in space group P21 after treatment with ebselen that revealed three key active-site loops (residues 33-44, 70-79, and 161-165) that are either disordered or in multiple conformations, supporting a hypothesis whereby dynamic conformational changes may be important for catalysis and ebselen inhibition. Using the thermal shift assay, we confirmed that ebselen significantly destabilizes the enzyme. Molecular docking suggests that ebselen could bind in the vicinity of His217. Investigation of the role of IMPase1 residues His217 and Cys218 suggests that inhibition of IMPase1 by ebselen may not be mediated via covalent modification of the active-site cysteine (Cys218) and is not affected by the covalent modification of other cysteine residues in the structure. Our results suggest that effects previously ascribed to ebselen-dependent inhibition likely result from disruption of essential active-site architecture, preventing activation of the IMPase1-Mg2+ complex.Communicated by Ramaswamy H. Sarma.


Asunto(s)
Cisteína , Compuestos de Organoselenio , Humanos , Simulación del Acoplamiento Molecular , Monoéster Fosfórico Hidrolasas/química , Litio/farmacología , Litio/uso terapéutico , Compuestos de Organoselenio/farmacología , Compuestos de Organoselenio/química
12.
Biophys J ; 122(11): 2267-2284, 2023 06 06.
Artículo en Inglés | MEDLINE | ID: mdl-36680342

RESUMEN

Voltage-sensing phosphatase (VSP) consists of the voltage sensor domain (VSD) similar to that of voltage-gated ion channels and the cytoplasmic phosphatase region with remarkable similarity to the phosphatase and tensin homolog deleted on chromosome 10 (PTEN). Membrane depolarization activates VSD, leading to dephosphorylation of three species of phosphoinositides (phosphatidylinositol phosphates (PIPs)), PI(3,4,5)P3, PI(4,5)P2, and PI(3,4)P2. VSP dephosphorylates 3- and 5-phosphate of PIPs, unlike PTEN, which shows rigid 3-phosphate specificity. In this study, a bioinformatics search showed that some mammals have VSP orthologs with amino acid diversity in the active center motif, Cx5R, which is highly conserved among protein tyrosine phosphatases and PTEN-related phosphatases; lysine next to the active site cysteine in the Cx5R motif was substituted for methionine in VSP orthologs of Tasmanian devil, koala, and prairie deer mouse, and leucine in opossum. Since lysine at the corresponding site in PTEN is known to be critical for enzyme activities, we attempted to address the significance of amino acid diversity among VSP orthologs at this site. K364 was changed to different amino acids in sea squirt VSP (Ci-VSP), and voltage-dependent phosphatase activity in Xenopus oocyte was studied using fluorescent probes for PI(4,5)P2 and PI(3,4)P2. All mutants retained both 5-phosphatase and 3-phosphatase activity, indicating that lysine at this site is dispensable for 3-phosphatase activity, unlike PTEN. Notably, K364M mutant showed increased activity both of 5-phosphatase and 3-phosphatase compared with the wild type (WT). It also showed slower kinetics of voltage sensor motion. Malachite green assay of K364M mutant did not show significant difference of phosphatase activity from WT, suggesting tighter interaction between substrate binding and voltage sensing. Mutation corresponding to K364M in the zebrafish VSP led to enhanced voltage-dependent dephosphorylation of PI(4,5)P2. Further studies will provide clues to understanding of substrate preference in PIPs phosphatases as well as to customization of a molecular tool.


Asunto(s)
Cisteína , Lisina , Animales , Dominio Catalítico , Pez Cebra , Monoéster Fosfórico Hidrolasas/química , Fosfatos de Fosfatidilinositol/metabolismo , Aminoácidos , Mamíferos/metabolismo
13.
J Inorg Biochem ; 239: 112064, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36410306

RESUMEN

We report the synthesis of a new asymmetric heptadentate ligand based on the 1,3-diaminopropan-2-ol backbone. The ligand 3-[[3-(bis-pyridin-2-ylmethyl-amino)-2-hydroxy-propyl]-(2-carbamoyl-ethyl)-amino]-propionamide (HL1) contains two amide and two pyridine groups attached to the 1,3-diaminopropan-2-ol core. Reaction between HL1 and Zn(ClO4)2.6H2O resulted in the formation of the dinuclear [Zn2(L1)(µ-OAc)](ClO4)2 complex, characterized by single crystal X-ray diffraction, 1H, 13C and 15N NMR, ESI-(+)-MS, CHN elemental analysis as well as infrared spectroscopy. The phosphatase activity of the complex was studied in the pH range 6-11 employing pyridinium bis(2,4-dinitrophenyl)phosphate (py(BDNPP)) as substrate. The complex exhibited activity dependent on the pH, presenting an asymmetric bell shape profile with the highest activity at pH 9; at high pH ligand exchange is rate-limiting. The hydrolysis of BDNPP- at pH 9 displayed behavior characteristic of Michaelis-Menten kinetics, with kcat = 5.06 × 10-3 min-1 and Km = 5.7 ± 1.0 mM. DFT calculations map out plausible reaction pathways and identify a terminal, Zn(II)-bound hydroxide as likely nucleophile.


Asunto(s)
Monoéster Fosfórico Hidrolasas , Zinc , Zinc/química , Ligandos , Hidrólisis , Cinética , Monoéster Fosfórico Hidrolasas/química , Cristalografía por Rayos X
14.
Protein Sci ; 32(1): e4536, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36502290

RESUMEN

The conservation of fold and chemistry of the enzymes associated with histidine biosynthesis suggests that this pathway evolved prior to the diversification of Bacteria, Archaea, and Eukaryotes. The only exception is the histidinol phosphate phosphatase (HolPase). So far, non-homologous HolPases that possess distinct folds and belong to three different protein superfamilies have been identified in various phylogenetic clades. However, their evolution has remained unknown to date. Here, we analyzed the evolutionary history of the HolPase from γ-Proteobacteria (HisB-N). It has been argued that HisB-N and its closest homologue d-glycero-d-manno-heptose-1,7-bisphosphate 7-phosphatase (GmhB) have emerged from the same promiscuous ancestral phosphatase. GmhB variants catalyze the hydrolysis of the anomeric d-glycero-d-manno-heptose-1,7-bisphosphate (αHBP or ßHBP) with a strong preference for one anomer (αGmhB or ßGmhB). We found that HisB-N from Escherichia coli shows promiscuous activity for ßHBP but not αHBP, while ßGmhB from Crassaminicella sp. shows promiscuous activity for HolP. Accordingly, a combined phylogenetic tree of αGmhBs, ßGmhBs, and HisB-N sequences revealed that HisB-Ns form a compact subcluster derived from ßGmhBs. Ancestral sequence reconstruction and in vitro analysis revealed a promiscuous HolPase activity in the resurrected enzymes prior to functional divergence of the successors. The following increase in catalytic efficiency of the HolP turnover is reflected in the shape and electrostatics of the active site predicted by AlphaFold. An analysis of the phylogenetic tree led to a revised evolutionary model that proposes the horizontal gene transfer of a promiscuous ßGmhB from δ- to γ-Proteobacteria where it evolved to the modern HisB-N.


Asunto(s)
Histidina , Monoéster Fosfórico Hidrolasas , Histidina/genética , Histidina/metabolismo , Filogenia , Monoéster Fosfórico Hidrolasas/genética , Monoéster Fosfórico Hidrolasas/química , Monoéster Fosfórico Hidrolasas/metabolismo , Histidinol-Fosfatasa/química , Escherichia coli/genética
15.
PLoS One ; 17(8): e0272015, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36044476

RESUMEN

Phylogenetic analysis, homology modelling and biochemical methods have been employed to characterize a phytase from a Gram-negative soil bacterium. Acinetobacter sp. AC1-2 phytase belongs to clade 2 of the histidine (acid) phytases, to the Multiple Inositol Polyphosphate Phosphatase (MINPP) subclass. The enzyme was extraordinarily stable in solution both at room temperature and 4°C, retaining near 100% activity over 755 days. It showed a broad pH activity profile from 2-8.5 with maxima at 3, 4.5-5 and 6. The enzyme showed Michaelis-Menten kinetics and substrate inhibition (Vmax, Km, and Ki, 228 U/mg, 0.65 mM and 2.23 mM, respectively). Homology modelling using the crystal structure of a homologous MINPP from a human gut commensal bacterium indicated the presence of a potentially stabilising polypeptide loop (a U-loop) straddling the active site. By employ of the enantiospecificity of Arabidopsis inositol tris/tetrakisphosphate kinase 1 for inositol pentakisphosphates, we show AC1-2 MINPP to possess D6-phytase activity, which allowed modelling of active site specificity pockets for InsP6 substrate. While phytase gene transcription was unaltered in rich media, it was repressed in minimal media with phytic acid and orthophosphate as phosphate sources. The results of this study reveal AC1-2 MINPP to possess desirable attributes relevant to biotechnological use.


Asunto(s)
6-Fitasa , Acinetobacter , Monoéster Fosfórico Hidrolasas , 6-Fitasa/química , 6-Fitasa/metabolismo , Acinetobacter/química , Acinetobacter/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Concentración de Iones de Hidrógeno , Fosfatos , Monoéster Fosfórico Hidrolasas/química , Monoéster Fosfórico Hidrolasas/metabolismo , Filogenia , Ácido Fítico , Microbiología del Suelo , Especificidad por Sustrato
16.
J Chem Inf Model ; 62(12): 3067-3078, 2022 06 27.
Artículo en Inglés | MEDLINE | ID: mdl-35670773

RESUMEN

Pseudomonas aeruginosa is a highly pathogenic Gram-negative microorganism associated with high mortality levels in burned or immunosuppressed patients or individuals affected by cystic fibrosis. Studies support a colonization mechanism whereby P. aeruginosa can breakdown the host cell membrane phospholipids through the sequential action of two enzymes: (I) hemolytic phospholipase C acting upon phosphatidylcholine or sphingomyelin to produce phosphorylcholine (Pcho) and (II) phosphorylcholine phosphatase (PchP) that hydrolyzes Pcho to generate choline and inorganic phosphate. This coordinated action provides the bacteria with carbon, nitrogen, and inorganic phosphate to support growth. Furthermore, PchP exhibits a distinctive inhibition mechanism by high substrate concentration. Here, we combine kinetic assays and computational approaches such as molecular docking, molecular dynamics, and free-energy calculations to describe the inhibitory site of PchP, which shares specific residues with the enzyme's active site. Our study provides insights into a coupled inhibition mechanism by the substrate, allowing us to postulate that the integrity of the inhibition site is needed to the correct functioning of the active site. Our results allow us to gain a better understanding of PchP function and provide the basis for a rational drug design that might contribute to the treatment of infections caused by this important opportunistic pathogen.


Asunto(s)
Monoéster Fosfórico Hidrolasas , Pseudomonas aeruginosa , Humanos , Simulación del Acoplamiento Molecular , Fosfatos/metabolismo , Monoéster Fosfórico Hidrolasas/química , Fosforilcolina/química , Fosforilcolina/farmacología , Pseudomonas aeruginosa/metabolismo
17.
Proc Natl Acad Sci U S A ; 119(26): e2200364119, 2022 06 28.
Artículo en Inglés | MEDLINE | ID: mdl-35733115

RESUMEN

Voltage-sensing phosphatase (VSP) consists of a voltage sensor domain (VSD) and a cytoplasmic catalytic region (CCR), which is similar to phosphatase and tensin homolog (PTEN). How the VSD regulates the innate enzyme component of VSP remains unclear. Here, we took a combined approach that entailed the use of electrophysiology, fluorometry, and structural modeling to study the electrochemical coupling in Ciona intestinalis VSP. We found that two hydrophobic residues at the lowest part of S4 play an essential role in the later transition of VSD-CCR coupling. Voltage clamp fluorometry and disulfide bond locking indicated that S4 and its neighboring linker move as one helix (S4-linker helix) and approach the hydrophobic spine in the CCR, a structure located near the cell membrane and also conserved in PTEN. We propose that the hydrophobic spine operates as a hub for translating an electrical signal into a chemical one in VSP.


Asunto(s)
Dominio Catalítico , Potenciales de la Membrana , Monoéster Fosfórico Hidrolasas , Dominios y Motivos de Interacción de Proteínas , Secuencia de Aminoácidos , Animales , Secuencia Conservada , Citoplasma/enzimología , Interacciones Hidrofóbicas e Hidrofílicas , Oocitos , Monoéster Fosfórico Hidrolasas/química , Monoéster Fosfórico Hidrolasas/genética , Xenopus laevis
18.
J Mol Biol ; 434(16): 167682, 2022 08 30.
Artículo en Inglés | MEDLINE | ID: mdl-35697294

RESUMEN

Disordered scaffold proteins provide multivalent landing pads that, via a series of embedded Short Linear Motifs (SLiMs), bring together the components of a complex to orchestrate precise spatial and temporal regulation of cellular processes. One such protein is AKAP5 (previously AKAP79), which contains SLiMs that anchor PKA and Calcineurin, and recruit substrate (the TRPV1 receptor). Calcineurin is anchored to AKAP5 by a well-characterised PxIxIT SLiM. Here we show, using a combination of biochemical and biophysical approaches, that the Calcineurin PxIxIT-binding groove also recognises several hitherto unknown lower-affinity SLiMs in addition to the PxIxIT motif. We demonstrate that the assembly is in reality a complex system with conserved SLiMs spanning a wide affinity range. The capture is analogous to that seen for many DNA-binding proteins that have a weak non-specific affinity for DNA outside the canonical binding site, but different in that it involves (i) two proteins, and (ii) hydrophobic rather than electrostatic interactions. It is also compatible with the requirement for both stable anchoring of the enzyme and responsive downstream signalling. We conclude that the AKAP5 C-terminus is enriched in lower-affinity/mini-SLiMs that, together with the canonical SLiM, maintain a structurally disordered but tightly regulated signalosome.


Asunto(s)
Proteínas de Anclaje a la Quinasa A , Calcineurina , Proteínas Intrínsecamente Desordenadas , Monoéster Fosfórico Hidrolasas , Proteínas de Anclaje a la Quinasa A/química , Calcineurina/química , Humanos , Proteínas Intrínsecamente Desordenadas/química , Monoéster Fosfórico Hidrolasas/química , Unión Proteica , Transducción de Señal
19.
Bioresour Technol ; 349: 126870, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35192947

RESUMEN

Bioremediation systems coupled to efficient microbial enzymes have emerged as an attractive approach for the in-situ removal of hazardous organophosphates (OPs) pesticides from the polluted environment. However, the role of engineered enzymes in OPs-degradation is rarely studied. In this study, the potential OPs-hydrolase (opdH) gene (Arthrobacter sp. HM01) was isolated, cloned, expressed, and purified. The recombinant organophosphate hydrolase (ropdH) was âˆ¼29 kDa; which catalyzed a broad-range of OPs-pesticides in organic-solvent (∼99 % in 30 min), and was found to increase the catalytic efficiency by 10-folds over the native enzyme (kcat/Km: 107 M-1s-1). The degraded metabolites were analyzed using HPLC/GCMS. Through site-directed mutagenesis, it was confirmed that, conserved metal-bridged residue (Lys-127), plays a crucial role in OPs-degradation, which shows âˆ¼18-folds decline in OPs-degradation. Furthermore, the catalytic activity and its stability has been enhanced by >2.0-fold through biochemical optimization. Thus, the study suggests that ropdH has all the required properties for OPs bioremediation.


Asunto(s)
Arthrobacter , Plaguicidas , Arthrobacter/genética , Arthrobacter/metabolismo , Compuestos Organofosforados/metabolismo , Plaguicidas/química , Monoéster Fosfórico Hidrolasas/química , Monoéster Fosfórico Hidrolasas/genética , Piperidinas
20.
Nat Commun ; 13(1): 827, 2022 02 11.
Artículo en Inglés | MEDLINE | ID: mdl-35149676

RESUMEN

Nanozyme is a collection of nanomaterials with enzyme-like activity but higher environmental tolerance and long-term stability than their natural counterparts. Improving the catalytic activity and expanding the category of nanozymes are prerequisites to complement or even supersede enzymes. However, the development of hydrolytic nanozymes is still challenged by diverse hydrolytic substrates and following complicated mechanisms. Here, two strategies are informed by data to screen and predict catalytic active sites of MOF (metal-organic framework) based hydrolytic nanozymes: (1) to increase the intrinsic activity by finely tuned Lewis acidity of the metal clusters; (2) to improve the density of active sites by shortening the length of ligands. Finally, as-obtained Ce-FMA-MOF-based hydrolytic nanozyme is capable of cleaving phosphate bonds, amide bonds, glycosidic bonds, and even their mixture, biofilms. This work provides a rational methodology to design hydrolytic nanozyme, enriches the diversity of nanozymes, and potentially sheds light on future evolution of enzyme engineering.


Asunto(s)
Enzimas/química , Enzimas/metabolismo , Nanoestructuras/química , Biopelículas/crecimiento & desarrollo , Catálisis , Dominio Catalítico , Glicósido Hidrolasas/química , Hidrólisis , Iones , Ligandos , Estructuras Metalorgánicas/química , Metales , Monoéster Fosfórico Hidrolasas/química
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