1
|
De Vitto H, Belfon KKJ, Sharma N, Toay S, Abendroth J, Dranow DM, Lukacs CM, Choi R, Udell HS, Willis S, Barrera G, Beyer O, Li TD, Hicks KA, Torelli AT, French JB. Characterization of an Acinetobacter baumannii Monofunctional Phosphomethylpyrimidine Kinase That Is Inhibited by Pyridoxal Phosphate. Biochemistry 2024. [PMID: 38306231 PMCID: PMC11426312 DOI: 10.1021/acs.biochem.3c00640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2024]
Abstract
Thiamin and its phosphate derivatives are ubiquitous molecules involved as essential cofactors in many cellular processes. The de novo biosynthesis of thiamin employs the parallel synthesis of 4-methyl-5-(2-hydroxyethyl)thiazole (THZ-P) and 4-amino-2-methyl-5(diphosphooxymethyl) pyrimidine (HMP) pyrophosphate (HMP-PP), which are coupled to generate thiamin phosphate. Most organisms that can biosynthesize thiamin employ a kinase (HMPK or ThiD) to generate HMP-PP. In nearly all cases, this enzyme is bifunctional and can also salvage free HMP, producing HMP-P, the monophosphate precursor of HMP-PP. Here we present high-resolution crystal structures of an HMPK from Acinetobacter baumannii (AbHMPK), both unliganded and with pyridoxal 5-phosphate (PLP) noncovalently bound. Despite the similarity between HMPK and pyridoxal kinase enzymes, our kinetics analysis indicates that AbHMPK accepts HMP exclusively as a substrate and cannot turn over pyridoxal, pyridoxamine, or pyridoxine nor does it display phosphatase activity. PLP does, however, act as a weak inhibitor of AbHMPK with an IC50 of 768 μM. Surprisingly, unlike other HMPKs, AbHMPK catalyzes only the phosphorylation of HMP and does not generate the diphosphate HMP-PP. This suggests that an additional kinase is present in A. baumannii, or an alternative mechanism is in operation to complete the biosynthesis of thiamin.
Collapse
Affiliation(s)
- Humberto De Vitto
- The Hormel Institute, University of Minnesota, Austin, Minnesota 55912, United States
| | - Kafi K J Belfon
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11790, United States
| | - Nandini Sharma
- The Hormel Institute, University of Minnesota, Austin, Minnesota 55912, United States
| | - Sarah Toay
- Department of Biological Chemistry, Grinnell College, Grinnell, Iowa 50112, United States
| | - Jan Abendroth
- UCB BioSciences, Bainbridge Island, Washington 98110, United States
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, Washington 98104, United States
| | - David M Dranow
- UCB BioSciences, Bainbridge Island, Washington 98110, United States
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, Washington 98104, United States
| | - Christine M Lukacs
- UCB BioSciences, Bainbridge Island, Washington 98110, United States
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, Washington 98104, United States
| | - Ryan Choi
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, Washington 98104, United States
| | - Hannah S Udell
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, Washington 98104, United States
| | - Sydney Willis
- Department of Chemistry, Rollins College, Winter Park, Florida 32789, United States
| | - George Barrera
- Department of Chemistry and Biochemistry, Weber State University, Ogden, Utah 84408, United States
| | - Olive Beyer
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, Baltimore, Maryland 21250, United States
| | - Teng Da Li
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11790, United States
| | - Katherine A Hicks
- Chemistry Department, State University of New York at Cortland, Cortland, New York 13045, United States
| | - Andrew T Torelli
- Department of Chemistry, Ithaca College, Ithaca, New York 14850, United States
| | - Jarrod B French
- The Hormel Institute, University of Minnesota, Austin, Minnesota 55912, United States
| |
Collapse
|
2
|
Gorelova V, Colinas M, Dell’Aglio E, Flis P, Salt DE, Fitzpatrick TB. Phosphorylated B6 vitamer deficiency in SALT OVERLY SENSITIVE 4 mutants compromises shoot and root development. PLANT PHYSIOLOGY 2022; 188:220-240. [PMID: 34730814 PMCID: PMC8774746 DOI: 10.1093/plphys/kiab475] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 09/05/2021] [Indexed: 05/31/2023]
Abstract
Stunted growth in saline conditions is a signature phenotype of the Arabidopsis SALT OVERLY SENSITIVE mutants (sos1-5) affected in pathways regulating the salt stress response. One of the mutants isolated, sos4, encodes a kinase that phosphorylates pyridoxal (PL), a B6 vitamer, forming the important coenzyme pyridoxal 5'-phosphate (PLP). Here, we show that sos4-1 and more recently isolated alleles are deficient in phosphorylated B6 vitamers including PLP. This deficit is concomitant with a lowered PL level. Ionomic profiling of plants under standard laboratory conditions (without salt stress) reveals that sos4 mutants are perturbed in mineral nutrient homeostasis, with a hyperaccumulation of transition metal micronutrients particularly in the root, accounting for stress sensitivity. This is coincident with the accumulation of reactive oxygen species, as well as enhanced lignification and suberization of the endodermis, although the Casparian strip is intact and functional. Further, micrografting shows that SOS4 activity in the shoot is necessary for proper root development. Growth under very low light alleviates the impairments, including salt sensitivity, suggesting that SOS4 is important for developmental processes under moderate light intensities. Our study provides a basis for the integration of SOS4 derived B6 vitamers into plant health and fitness.
Collapse
Affiliation(s)
- Vera Gorelova
- Department of Botany and Plant Biology, University of Geneva, 1211 Geneva, Switzerland
| | - Maite Colinas
- Department of Botany and Plant Biology, University of Geneva, 1211 Geneva, Switzerland
| | - Elisa Dell’Aglio
- Department of Botany and Plant Biology, University of Geneva, 1211 Geneva, Switzerland
| | - Paulina Flis
- Future Food Beacon of Excellence and School of Biosciences, University of Nottingham, Leicestershire LE12 5RD, UK
| | - David E Salt
- Future Food Beacon of Excellence and School of Biosciences, University of Nottingham, Leicestershire LE12 5RD, UK
| | - Teresa B Fitzpatrick
- Department of Botany and Plant Biology, University of Geneva, 1211 Geneva, Switzerland
| |
Collapse
|
3
|
Goberna-Bravo MÁ, Albiol-Chiva J, Peris-Vicente J, Carda-Broch S, Esteve-Romero J. Determination of isoniazid and pyridoxine in plasma sample of tuberculosis patients by micellar liquid chromatography. Microchem J 2021. [DOI: 10.1016/j.microc.2021.106317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
4
|
Ghatge MS, Al Mughram M, Omar AM, Safo MK. Inborn errors in the vitamin B6 salvage enzymes associated with neonatal epileptic encephalopathy and other pathologies. Biochimie 2021; 183:18-29. [PMID: 33421502 PMCID: PMC11273822 DOI: 10.1016/j.biochi.2020.12.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 12/28/2020] [Accepted: 12/30/2020] [Indexed: 12/28/2022]
Abstract
Pyridoxal 5'-phosphate (PLP), the active cofactor form of vitamin B6 is required by over 160 PLP-dependent (vitamin B6) enzymes serving diverse biological roles, such as carbohydrates, amino acids, hemes, and neurotransmitters metabolism. Three key enzymes, pyridoxal kinase (PL kinase), pyridoxine 5'-phosphate oxidase (PNPO), and phosphatases metabolize and supply PLP to PLP-dependent enzymes through the salvage pathway. In born errors in the salvage enzymes are known to cause inadequate levels of PLP in the cell, particularly in neuronal cells. The resulting PLP deficiency is known to cause or implicated in several pathologies, most notably seizures. One such disorder, PNPO-dependent neonatal epileptic encephalopathy (NEE) results from natural mutations in PNPO and leads to null or reduced enzymatic activity. NEE does not respond to conventional antiepileptic drugs but may respond to treatment with the B6 vitamers PLP and/or pyridoxine (PN). In born errors that lead to PLP deficiency in cells have also been reported in PL kinase, however, to date none has been associated with epilepsy or seizure. One such pathology is polyneuropathy that responds to PLP therapy. Phosphatase deficiency or hypophosphatasia disorder due to pathogenic mutations in alkaline phosphatase is known to cause seizures that respond to PN therapy. In this article, we review the biochemical features of in born errors pertaining to the salvage enzyme's deficiency that leads to NEE and other pathologies. We also present perspective on vitamin B6 treatment for these disorders, along with attempts to develop zebrafish model to study the NEE syndrome in vivo.
Collapse
Affiliation(s)
- Mohini S Ghatge
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA; Institute for Structural Biology, Drug Discovery, and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Mohammed Al Mughram
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA; Institute for Structural Biology, Drug Discovery, and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Abdelsattar M Omar
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Alsulaymanyah, Jeddah, 21589, Saudi Arabia; Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Al-Azhar University, Cairo, 11884, Egypt
| | - Martin K Safo
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA; Institute for Structural Biology, Drug Discovery, and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA.
| |
Collapse
|
5
|
Gonzalez-Ordenes F, Bravo-Moraga F, Gonzalez E, Hernandez-Cabello L, Alzate-Morales J, Guixé V, Castro-Fernandez V. Crystal structure and molecular dynamics simulations of a promiscuous ancestor reveal residues and an epistatic interaction involved in substrate binding and catalysis in the ATP-dependent vitamin kinase family members. Protein Sci 2021; 30:842-854. [PMID: 33555078 DOI: 10.1002/pro.4040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 02/03/2021] [Accepted: 02/05/2021] [Indexed: 11/08/2022]
Abstract
Enzymes with hydroxymethylpyrimidine/phosphomethylpyrimidine kinase activity (HMPPK) are essential in the vitamin B1 (thiamine pyrophosphate) biosynthesis and recycling pathways. In contrast, enzymes with pyridoxal kinase activity (PLK) produce pyridoxal phosphate (vitamin B6), an essential cofactor for various biochemical reactions. In the ATP-dependent vitamin kinases family, the members of PLK/HMPPK-like subfamily have both enzymatic activities. It has been proposed that the promiscuous PLK activity of ancestral HMPPK enzymes could have been the starting point for this activity. In earlier work, we reconstructed the ancestral sequences of this family and characterized the substrate specificity of the common ancestor between PLK/HMPPK-like and HMPPK enzymes (AncC). From these studies, the Gln45Met mutation was proposed as a critical event for the PLK activity emergence. Here, we crystallize and determine the AncC structure by X-ray crystallography and assess the role of the Gln45Met mutation by site-directed mutagenesis. Kinetic characterization of this mutant shows a significant increase in the PL affinity. Through molecular dynamics simulation and MM/PBSA calculations some residues, important for substrate interactions and catalysis, were identified in the wild type and in the mutated ancestor. Interestingly, a strong epistatic interaction responsible for the evolutionary pathway of the PLK activity in PLK/HMPPK-like enzymes was revealed. Also, other putative mutations relevant to PLK activity in modern PLK/HMPPK-like enzymes were identified.
Collapse
Affiliation(s)
| | - Felipe Bravo-Moraga
- Centro de Bioinformatica, Simulación y Modelado (CBSM), Facultad de Ingeniería, Universidad de Talca, Campus Lircay S/N, Talca, Chile
| | - Evelin Gonzalez
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | | | - Jans Alzate-Morales
- Centro de Bioinformatica, Simulación y Modelado (CBSM), Facultad de Ingeniería, Universidad de Talca, Campus Lircay S/N, Talca, Chile
| | - Victoria Guixé
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | | |
Collapse
|
6
|
An Evolutionary Marker of the Ribokinase Superfamily Is Responsible for Zinc-Mediated Regulation of Human Pyridoxal Kinase. Catalysts 2020. [DOI: 10.3390/catal10050555] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The ribokinase superfamily catalyzes the phosphorylation of a vast diversity of substrates, and its members are characterized by the conservation of a common structural fold along with highly conserved sequence motifs responsible for phosphoryl transfer (GXGD) and stabilization of the metal-nucleotide complex (NXXE). Recently, a third motif (HXE) exclusive from ADP-dependent enzymes was identified, with its glutamic acid participating in water-mediated interactions with the metal-nucleotide complex and in stabilization of the ternary complex during catalysis. In this work, we bioinformatically determine that the aspartic acid of another motif (DPV), exclusively found in hydroxyethyl thiazole (THZK), hydroxymethyl pyrimidine (HMPK) and pyridoxal kinases (PLK), is structurally equivalent to the acidic residue in the HXE motif. Moreover, this residue is highly conserved among all ribokinase superfamily members. To determine whether the functional role of the DPV motif is similar to the HXE motif, we employed molecular dynamics simulations using crystal structures of phosphoryl donor substrate-complexed THZK and PLK, showing that its aspartic acid participated in water-mediated or direct interactions with the divalent metal of the metal-nucleotide complex. Lastly, enzyme kinetic assays on human PLK, an enzyme that utilizes zinc, showed that site-directed mutagenesis of the aspartic acid from the DPV motif abolishes the inhibition of this enzyme by increasing free zinc concentrations. Altogether, our results highlight that the DPV and HXE motifs are evolutionary markers of the functional and structural divergence of the ribokinase superfamily and evidence the role of the DPV motif in the interaction with both free and nucleotide-complexed divalent metals in the binding site of these enzymes.
Collapse
|
7
|
Cea PA, Araya G, Vallejos G, Recabarren R, Alzate-Morales J, Babul J, Guixé V, Castro-Fernandez V. Characterization of hydroxymethylpyrimidine phosphate kinase from mesophilic and thermophilic bacteria and structural insights into their differential thermal stability. Arch Biochem Biophys 2020; 688:108389. [PMID: 32387178 DOI: 10.1016/j.abb.2020.108389] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/03/2020] [Accepted: 04/21/2020] [Indexed: 02/01/2023]
Abstract
The hydroxymethylpyrimidine phosphate kinases (HMPPK) encoded by the thiD gene are involved in the thiamine biosynthesis pathway, can perform two consecutive phosphorylations of 4-amino-5-hydroxymethyl-2-methyl pyrimidine (HMP) and are found in thermophilic and mesophilic bacteria, but only a few characterizations of mesophilic enzymes are available. The presence of another homolog enzyme (pyridoxal kinase) that can only catalyze the first phosphorylation of HMP and encoded by pdxK gene, has hampered a precise annotation in this enzyme family. Here we report the kinetic characterization of two HMPPK with structure available, the mesophilic and thermophilic enzyme from Salmonella typhimurium (StHMPPK) and Thermus thermophilus (TtHMPPK), respectively. Also, given their high structural similarity, we have analyzed the structural determinants of protein thermal stability in these enzymes by molecular dynamics simulation. The results show that pyridoxal kinases (PLK) from gram-positive bacteria (PLK/HMPPK-like enzymes) constitute a phylogenetically separate group from the canonical PLK, but closely related to the HMPPK, so the PLK/HMPPK-like and canonical PLK, both encoded by pdxK genes, are different and must be annotated distinctly. The kinetic characterization of StHMPPK and TtHMPPK, shows that they perform double phosphorylation on HMP, both enzymes are specific for HMP, not using pyridoxal-like molecules as substrates and their kinetic mechanism involves the formation of a ternary complex. Molecular dynamics simulation shows that StHMPPK and TtHMPPK have striking differences in their conformational flexibility, which can be correlated with the hydrophobic packing and electrostatic interaction network given mainly by salt bridge bonds, but interestingly not by the number of hydrogen bond interactions as reported for other thermophilic enzymes. ENZYMES: EC 2.7.1.49, EC 2.7.4.7, EC 2.7.1.35, EC 2.7.1.50.
Collapse
Affiliation(s)
- Pablo A Cea
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Gissela Araya
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Gabriel Vallejos
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Rodrigo Recabarren
- Centro de Bioinformática, Simulación y Modelado, Facultad de Ingeniería, Universidad de Talca, Talca, Chile
| | - Jans Alzate-Morales
- Centro de Bioinformática, Simulación y Modelado, Facultad de Ingeniería, Universidad de Talca, Talca, Chile
| | - Jorge Babul
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Victoria Guixé
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | | |
Collapse
|
8
|
Barra ALC, Dantas LDOC, Morão LG, Gutierrez RF, Polikarpov I, Wrenger C, Nascimento AS. Essential Metabolic Routes as a Way to ESKAPE From Antibiotic Resistance. Front Public Health 2020; 8:26. [PMID: 32257985 PMCID: PMC7093009 DOI: 10.3389/fpubh.2020.00026] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/27/2020] [Indexed: 02/03/2023] Open
Abstract
Antibiotic resistance is a worldwide concern that requires a concerted action from physicians, patients, governmental agencies, and academia to prevent infections and the spread of resistance, track resistant bacteria, improve the use of current antibiotics, and develop new antibiotics. Despite the efforts spent so far, the current antibiotics in the market are restricted to only five general targets/pathways highlighting the need for basic research focusing on the discovery and evaluation of new potential targets. Here we interrogate two biosynthetic pathways as potentially druggable pathways in bacteria. The biosynthesis pathway for thiamine (vitamin B1), absent in humans, but found in many bacteria, including organisms in the group of the ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacter sp.) and the biosynthesis pathway for pyridoxal 5'-phosphate and its vitamers (vitamin B6), found in S. aureus. Using current genomic data, we discuss the possibilities of inhibition of enzymes in the pathway and review the current state of the art in the scientific literature.
Collapse
Affiliation(s)
| | | | - Luana Galvão Morão
- São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
| | - Raíssa F. Gutierrez
- São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
| | - Igor Polikarpov
- São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
| | - Carsten Wrenger
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | | |
Collapse
|
9
|
Are S, Gatreddi S, Jakkula P, Qureshi IA. Structural attributes and substrate specificity of pyridoxal kinase from Leishmania donovani. Int J Biol Macromol 2020; 152:812-827. [PMID: 32105687 DOI: 10.1016/j.ijbiomac.2020.02.257] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 02/22/2020] [Accepted: 02/23/2020] [Indexed: 11/26/2022]
Abstract
The enzyme pyridoxal kinase (PdxK) catalyzes the conversion of pyridoxal to pyridoxal-5'-phosphate (PLP) using ATP as the co-factor. The product pyridoxal-5'-phosphate plays a key role in several biological processes such as transamination, decarboxylation and deamination. In the present study, full-length ORF of PdxK from Leishmania donovani (LdPdxK) was cloned and then purified using affinity chromatography. LdPdxK exists as a homo-dimer in solution and shows more activity at near to physiological pH. Biochemical analysis of LdPdxK with pyridoxal, pyridoxamine, pyridoxine and ginkgotoxin revealed its affinity preference towards different substrates. The secondary structure analysis using circular dichroism spectroscopy showed LdPdxK to be predominantly α-helical in organization which tends to decline at lower and higher pH. Simultaneously, LdPdxK was crystallized and its three-dimensional structure in complex with ADP and different substrates were determined. Crystal structure of LdPdxK delineated that it has a central core of β-sheets surrounded by α-helices with a conserved GTGD ribokinase motif. The structures of LdPdxK disclosed no major structural changes between ADP and ADP- substrate bound structures. In addition, comparative structural analysis highlighted the key differences between the active site pockets of leishmanial and human PdxK, rendering LdPdxK an attractive candidate for the designing of novel and specific inhibitors.
Collapse
Affiliation(s)
- Sayanna Are
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, Telangana, India
| | - Santhosh Gatreddi
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, Telangana, India
| | - Pranay Jakkula
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, Telangana, India
| | - Insaf Ahmed Qureshi
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, Telangana, India.
| |
Collapse
|
10
|
Deka G, Kalyani JN, Jahangir FB, Sabharwal P, Savithri HS, Murthy MRN. Structural and functional studies on Salmonella typhimurium pyridoxal kinase: the first structural evidence for the formation of Schiff base with the substrate. FEBS J 2019; 286:3684-3700. [PMID: 31116912 DOI: 10.1111/febs.14933] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 02/07/2019] [Accepted: 05/20/2019] [Indexed: 11/29/2022]
Abstract
A large number of enzymes depend on the ubiquitous cofactor pyridoxal 5' phosphate (PLP) for their activity. Pyridoxal kinase (PLK) is the key enzyme involved in the synthesis of PLP from the three forms of vitamin B6 via the salvage pathway. In the present work, we determined the unliganded structure of StPLK in a monoclinic form and its ternary complex with bound pyridoxal (PL), ADP and Mg2+ in two different tetragonal crystal forms (Form I and Form II). We found that, in the ternary complex structure of StPLK, the active site Lys233 forms a Schiff base linkage with the substrate (PL). Although formation of a Schiff base with the active site Lys229 was demonstrated in the Escherichia coli enzyme based on biochemical studies, the ternary complex of StPLK represents the first crystal structure where the Schiff bond formation has been observed. We also identified an additional site for PLP binding away from the active site in one of the ternary complexes (crystal Form I), suggesting a probable route for the product release. This is the first ternary complex structure where the modeled γ-phosphate of ATP is close enough to PL for the phosphorylation of the substrate. StPLK prefers PL over pyridoxamine as its substrate and follows a sequential mechanism of catalysis. Surface plasmon resonance studies suggest that StPLK interacts with apo-PLP-dependent enzymes with μm affinity supporting the earlier proposed direct transfer mechanism of PLP from PLK to PLP-dependent enzymes.
Collapse
Affiliation(s)
- Geeta Deka
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Josyula N Kalyani
- Biochemistry Department, Indian Institute of Science, Bangalore, India
| | | | - Pallavi Sabharwal
- Biochemistry Department, Indian Institute of Science, Bangalore, India
| | | | - Mathur R N Murthy
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| |
Collapse
|
11
|
Richts B, Rosenberg J, Commichau FM. A Survey of Pyridoxal 5'-Phosphate-Dependent Proteins in the Gram-Positive Model Bacterium Bacillus subtilis. Front Mol Biosci 2019; 6:32. [PMID: 31134210 PMCID: PMC6522883 DOI: 10.3389/fmolb.2019.00032] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 04/18/2019] [Indexed: 11/13/2022] Open
Abstract
The B6 vitamer pyridoxal 5′-phosphate (PLP) is a co-factor for proteins and enzymes that are involved in diverse cellular processes. Therefore, PLP is essential for organisms from all kingdoms of life. Here we provide an overview about the PLP-dependent proteins from the Gram-positive soil bacterium Bacillus subtilis. Since B. subtilis serves as a model system in basic research and as a production host in industry, knowledge about the PLP-dependent proteins could facilitate engineering the bacteria for biotechnological applications. The survey revealed that the majority of the PLP-dependent proteins are involved in metabolic pathways like amino acid biosynthesis and degradation, biosynthesis of antibacterial compounds, utilization of nucleotides as well as in iron and carbon metabolism. Many PLP-dependent proteins participate in de novo synthesis of the co-factors biotin, folate, heme, and NAD+ as well as in cell wall metabolism, tRNA modification, regulation of gene expression, sporulation, and biofilm formation. A surprisingly large group of PLP-dependent proteins (29%) belong to the group of poorly characterized proteins. This review underpins the need to characterize the PLP-dependent proteins of unknown function to fully understand the “PLP-ome” of B. subtilis.
Collapse
Affiliation(s)
- Björn Richts
- Department of General Microbiology, University of Goettingen, Göttingen, Germany
| | - Jonathan Rosenberg
- Department of General Microbiology, University of Goettingen, Göttingen, Germany
| | - Fabian M Commichau
- Department of General Microbiology, University of Goettingen, Göttingen, Germany
| |
Collapse
|
12
|
Murillo-López J, Zinovjev K, Pereira H, Caniuguir A, Garratt R, Babul J, Recabarren R, Alzate-Morales J, Caballero J, Tuñón I, Cabrera R. Studying the phosphoryl transfer mechanism of the E. coli phosphofructokinase-2: from X-ray structure to quantum mechanics/molecular mechanics simulations. Chem Sci 2019; 10:2882-2892. [PMID: 30996866 PMCID: PMC6429617 DOI: 10.1039/c9sc00094a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 01/24/2019] [Indexed: 12/31/2022] Open
Abstract
Phosphofructokinases catalyze the ATP-dependent phosphorylation of fructose-6-phosphate and they are highly regulated.
Phosphofructokinases (Pfks) catalyze the ATP-dependent phosphorylation of fructose-6-phosphate (F6P) and they are regulated in a wide variety of organisms. Although numerous aspects of the kinetics and regulation have been characterized for Pfks, the knowledge about the mechanism of the phosphoryl transfer reaction and the transition state lags behind. In this work, we describe the X-ray crystal structure of the homodimeric Pfk-2 from E. coli, which contains products in one site and reactants in the other, as well as an additional ATP molecule in the inhibitory allosteric site adjacent to the reactants. This complex was previously predicted when studying the kinetic mechanism of ATP inhibition. After removing the allosteric ATP, molecular dynamic (MD) simulations revealed conformational changes related to domain packing, as well as stable interactions of Lys27 and Asp256 with donor (ATP) and acceptor (fructose-6-) groups, and of Asp166 with Mg2+. The phosphoryl transfer reaction mechanism catalyzed by Pfk-2 was investigated through Quantum Mechanics/Molecular Mechanics (QM/MM) simulations using a combination of the string method and a path-collective variable for the exploration of its free energy surface. The calculated activation free energies showed that a dissociative mechanism, occurring with a metaphosphate intermediate formation followed by a proton transfer to Asp256, is more favorable than an associative one. The structural analysis reveals the role of Asp256 acting as a catalytic base and Lys27 stabilizing the transition state of the dissociative mechanism.
Collapse
Affiliation(s)
- Juliana Murillo-López
- Centro de Bioinformática y Simulación Molecular (CBSM) , Facultad de Ingeniería , Universidad de Talca , 1 Poniente 1141 , Talca , Chile .
| | - Kirill Zinovjev
- Departament de Química Física , Universitat de València , 46100 Burjassot , Spain .
| | - Humberto Pereira
- Instituto de Física de São Carlos , Universidade de São Paulo , São Paulo , Brazil
| | - Andres Caniuguir
- Departamento de Biología , Facultad de Ciencias , Universidad de Chile , Santiago , Chile .
| | - Richard Garratt
- Instituto de Física de São Carlos , Universidade de São Paulo , São Paulo , Brazil
| | - Jorge Babul
- Departamento de Biología , Facultad de Ciencias , Universidad de Chile , Santiago , Chile .
| | - Rodrigo Recabarren
- Centro de Bioinformática y Simulación Molecular (CBSM) , Facultad de Ingeniería , Universidad de Talca , 1 Poniente 1141 , Talca , Chile .
| | - Jans Alzate-Morales
- Centro de Bioinformática y Simulación Molecular (CBSM) , Facultad de Ingeniería , Universidad de Talca , 1 Poniente 1141 , Talca , Chile .
| | - Julio Caballero
- Centro de Bioinformática y Simulación Molecular (CBSM) , Facultad de Ingeniería , Universidad de Talca , 1 Poniente 1141 , Talca , Chile .
| | - Iñaki Tuñón
- Departament de Química Física , Universitat de València , 46100 Burjassot , Spain .
| | - Ricardo Cabrera
- Departamento de Biología , Facultad de Ciencias , Universidad de Chile , Santiago , Chile .
| |
Collapse
|
13
|
Nagata R, Fujihashi M, Sato T, Atomi H, Miki K. Crystal Structure and Product Analysis of an Archaeal myo-Inositol Kinase Reveal Substrate Recognition Mode and 3-OH Phosphorylation. Biochemistry 2015; 54:3494-503. [DOI: 10.1021/acs.biochem.5b00296] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ryuhei Nagata
- Department
of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Masahiro Fujihashi
- Department
of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Takaaki Sato
- Department
of Synthetic Chemistry and Biological Chemistry, Graduate School of
Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
- JST, CREST, 7, Gobancho, Chiyoda-ku, Tokyo 102-0076, Japan
| | - Haruyuki Atomi
- Department
of Synthetic Chemistry and Biological Chemistry, Graduate School of
Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
- JST, CREST, 7, Gobancho, Chiyoda-ku, Tokyo 102-0076, Japan
| | - Kunio Miki
- Department
of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
- JST, CREST, 7, Gobancho, Chiyoda-ku, Tokyo 102-0076, Japan
| |
Collapse
|
14
|
Castro-Fernandez V, Bravo-Moraga F, Ramirez-Sarmiento CA, Guixe V. Emergence of pyridoxal phosphorylation through a promiscuous ancestor during the evolution of hydroxymethyl pyrimidine kinases. FEBS Lett 2014; 588:3068-73. [PMID: 24952356 DOI: 10.1016/j.febslet.2014.06.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 06/05/2014] [Accepted: 06/06/2014] [Indexed: 11/24/2022]
Abstract
In the family of ATP-dependent vitamin kinases, several bifunctional enzymes that phosphorylate hydroxymethyl pyrimidine (HMP) and pyridoxal (PL) have been described besides enzymes specific towards HMP. To determine how bifunctionality emerged, we reconstructed the sequence of three ancestors of HMP kinases, experimentally resurrected, and assayed the enzymatic activity of their last common ancestor. The latter has ∼ 8-fold higher specificity for HMP due to a glutamine residue (Gln44) that is a key determinant of the specificity towards HMP, although it is capable of phosphorylating both substrates. These results show how a specific enzyme with catalytic promiscuity gave rise to current bifunctional enzymes.
Collapse
Affiliation(s)
| | - Felipe Bravo-Moraga
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | | | - Victoria Guixe
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
| |
Collapse
|
15
|
Deka G, Kalyani JN, Benazir JF, Savithri HS, Murthy MRN. Successful data recovery from oscillation photographs containing strong polycrystalline diffraction rings from an unknown small-molecule contaminant: preliminary structure solution of Salmonella typhimurium pyridoxal kinase (PdxK). Acta Crystallogr F Struct Biol Commun 2014; 70:526-9. [PMID: 24699755 PMCID: PMC3976079 DOI: 10.1107/s2053230x14005342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 03/08/2014] [Indexed: 11/10/2022] Open
Abstract
Pyridoxal kinase (PdxK; EC 2.7.1.35) belongs to the phosphotransferase family of enzymes and catalyzes the conversion of the three active forms of vitamin B6, pyridoxine, pyridoxal and pyridoxamine, to their phosphorylated forms and thereby plays a key role in pyridoxal 5'-phosphate salvage. In the present study, pyridoxal kinase from Salmonella typhimurium was cloned and overexpressed in Escherichia coli, purified using Ni-NTA affinity chromatography and crystallized. X-ray diffraction data were collected to 2.6 Å resolution at 100 K. The crystal belonged to the primitive orthorhombic space group P212121, with unit-cell parameters a = 65.11, b = 72.89, c = 107.52 Å. The data quality obtained by routine processing was poor owing to the presence of strong diffraction rings caused by a polycrystalline material of an unknown small molecule in all oscillation images. Excluding the reflections close to powder/polycrystalline rings provided data of sufficient quality for structure determination. A preliminary structure solution has been obtained by molecular replacement with the Phaser program in the CCP4 suite using E. coli pyridoxal kinase (PDB entry 2ddm) as the phasing model. Further refinement and analysis of the structure are likely to provide valuable insights into catalysis by pyridoxal kinases.
Collapse
Affiliation(s)
- G. Deka
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - J. N. Kalyani
- Biochemistry Department, Indian Institute of Science, Bangalore 560 012, India
| | - J. F. Benazir
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - H. S. Savithri
- Biochemistry Department, Indian Institute of Science, Bangalore 560 012, India
| | - M. R. N. Murthy
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| |
Collapse
|
16
|
Nodwell MB, Koch MF, Alte F, Schneider S, Sieber SA. A subfamily of bacterial ribokinases utilizes a hemithioacetal for pyridoxal phosphate salvage. J Am Chem Soc 2014; 136:4992-9. [PMID: 24601602 DOI: 10.1021/ja411785r] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pyridoxal 5'-phosphate (PLP) is the active vitamer of vitamin B6 and acts as an essential cofactor in many aspects of amino acid and sugar metabolism. The virulence and survival of pathogenic bacteria such as Mycobacterium tuberculosis depend on PLP, and deficiencies in humans have also been associated with neurological disorders and inflammation. While PLP can be synthesized by a de novo pathway in bacteria and plants, most higher organisms rely on a salvage pathway that phosphorylates either pyridoxal (PL) or its related vitamers, pyridoxine (PN) and pyridoxamine (PM). PL kinases (PLKs) are essential for this phosphorylation step and are thus of major importance for cellular viability. We recently identified a pyridoxal kinase (SaPLK) as a target of the natural product antibiotic rugulactone (Ru) in Staphylococcus aureus. Surprisingly, Ru selectively modified SaPLK not at the active site cysteine, but on a remote cysteine residue. Based on structural and biochemical studies, we now provide insight into an unprecedented dual Cys charge relay network that is mandatory for PL phosphorylation. The key component is the reactive Cys 110 residue in the lid region that forms a hemithioactetal intermediate with the 4'-aldehyde of PL. This hemithioacetal, in concert with the catalytic Cys 214, increases the nucleophilicity of the PL 5'-OH group for the inline displacement reaction with the γ-phosphate of ATP. A closer inspection of related enzymes reveals that Cys 110 is conserved and thus serves as a characteristic mechanistic feature for a dual-function ribokinase subfamily herein termed CC-PLKs.
Collapse
Affiliation(s)
- Matthew B Nodwell
- Organic Chemistry II, Centre for Integrated Protein Science CIPSM, Institute of Advanced Studies, and ‡Biochemistry, Department of Chemistry, Technische Universität München , Lichtenbergstrasse 4, 85747 Garching, Germany
| | | | | | | | | |
Collapse
|
17
|
Navarro F, Ramírez-Sarmiento CA, Guixé V. Catalytic and regulatory roles of species involved in metal-nucleotide equilibriums in human pyridoxal kinase. Biometals 2013; 26:805-12. [PMID: 23860900 DOI: 10.1007/s10534-013-9660-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 07/10/2013] [Indexed: 10/26/2022]
Abstract
Pyridoxal 5'-phosphate is the active form of vitamin B6 and its deficiency is directly related with several human disorders, which make human pyridoxal kinase (hPLK) an important pharmacologic target. In spite of this, a carefully kinetic characterization of hPLK including the main species that regulates the enzymatic activity is at date missing. Here we analyse the catalytic and regulatory mechanisms of hPLK as a function of a precise determination of the species involved in metal-nucleotide equilibriums and describe new regulatory mechanisms for this enzyme. hPLK activity is supported by several metals, being Zn(2+) the most effective, although the magnitude of the effect observed is highly dependent on the relative concentrations of metal and nucleotide used. The true substrate for the reaction catalyzed by hPLK is the metal nucleotide complex, while ATP(4-) and HATP(3-) did not affect the activity. The enzyme presents substrate inhibition by both pyridoxal (PL) and ZnATP(2-), although the latter behaves as a weakly inhibitor. Our study also established, for the first time, a dual role for free Zn(2+); as an activator at low concentrations (19 μM optimal concentration) and as a potent inhibitor with a IC50 of 37 μM. These results highlighted the importance of an accurate estimation of the actual concentration of the species involved in metal-nucleotide equilibriums in order to obtain reliable values for the kinetic parameters, and for determine the true regulators of the PLK activity. They also help to explain the dissimilar kinetic parameters reported in the literature for this enzyme.
Collapse
Affiliation(s)
- Freddy Navarro
- Laboratorio de Bioquímica y Biología Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile
| | | | | |
Collapse
|
18
|
Ghatge MS, Contestabile R, di Salvo ML, Desai JV, Gandhi AK, Camara CM, Florio R, González IN, Parroni A, Schirch V, Safo MK. Pyridoxal 5'-phosphate is a slow tight binding inhibitor of E. coli pyridoxal kinase. PLoS One 2012; 7:e41680. [PMID: 22848564 PMCID: PMC3404986 DOI: 10.1371/journal.pone.0041680] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 06/24/2012] [Indexed: 11/18/2022] Open
Abstract
Pyridoxal 5′-phosphate (PLP) is a cofactor for dozens of B6 requiring enzymes. PLP reacts with apo-B6 enzymes by forming an aldimine linkage with the ε-amino group of an active site lysine residue, thus yielding the catalytically active holo-B6 enzyme. During protein turnover, the PLP is salvaged by first converting it to pyridoxal by a phosphatase and then back to PLP by pyridoxal kinase. Nonetheless, PLP poses a potential toxicity problem for the cell since its reactive 4′-aldehyde moiety forms covalent adducts with other compounds and non-B6 proteins containing thiol or amino groups. The regulation of PLP homeostasis in the cell is thus an important, yet unresolved issue. In this report, using site-directed mutagenesis, kinetic, spectroscopic and chromatographic studies we show that pyridoxal kinase from E. coli forms a complex with the product PLP to form an inactive enzyme complex. Evidence is presented that, in the inhibited complex, PLP has formed an aldimine bond with an active site lysine residue during catalytic turnover. The rate of dissociation of PLP from the complex is very slow, being only partially released after a 2-hour incubation with PLP phosphatase. Interestingly, the inactive pyridoxal kinase•PLP complex can be partially reactivated by transferring the tightly bound PLP to an apo-B6 enzyme. These results open new perspectives on the mechanism of regulation and role of pyridoxal kinase in the Escherichia coli cell.
Collapse
Affiliation(s)
- Mohini S. Ghatge
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Roberto Contestabile
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche, Sapienza Università di Roma, Roma, Italy
| | - Martino L. di Salvo
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche, Sapienza Università di Roma, Roma, Italy
| | - Jigar V. Desai
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Amit K. Gandhi
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Christina M. Camara
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Rita Florio
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche, Sapienza Università di Roma, Roma, Italy
| | - Isabel N. González
- Consiglio Nazionale delle Ricerche, Istituto di Biologia Agroambientale e Forestale, Monterotondo Scalo, Roma, Italy
- Institute of Biocomputation and Physics of Complex Systems, Universidad de Zaragoza, Zaragoza, Spain
| | - Alessia Parroni
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche, Sapienza Università di Roma, Roma, Italy
| | - Verne Schirch
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Martin K. Safo
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
- * E-mail:
| |
Collapse
|
19
|
Gandhi AK, Desai JV, Ghatge MS, di Salvo ML, Di Biase S, Danso-Danquah R, Musayev FN, Contestabile R, Schirch V, Safo MK. Crystal structures of human pyridoxal kinase in complex with the neurotoxins, ginkgotoxin and theophylline: insights into pyridoxal kinase inhibition. PLoS One 2012; 7:e40954. [PMID: 22879864 PMCID: PMC3412620 DOI: 10.1371/journal.pone.0040954] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 06/15/2012] [Indexed: 11/18/2022] Open
Abstract
Several drugs and natural compounds are known to be highly neurotoxic, triggering epileptic convulsions or seizures, and causing headaches, agitations, as well as other neuronal symptoms. The neurotoxic effects of some of these compounds, including theophylline and ginkgotoxin, have been traced to their inhibitory activity against human pyridoxal kinase (hPL kinase), resulting in deficiency of the active cofactor form of vitamin B₆, pyridoxal 5'-phosphate (PLP). Pyridoxal (PL), an inactive form of vitamin B₆ is converted to PLP by PL kinase. PLP is the B₆ vitamer required as a cofactor for over 160 enzymatic activities essential in primary and secondary metabolism. We have performed structural and kinetic studies on hPL kinase with several potential inhibitors, including ginkgotoxin and theophylline. The structural studies show ginkgotoxin and theophylline bound at the substrate site, and are involved in similar protein interactions as the natural substrate, PL. Interestingly, the phosphorylated product of ginkgotoxin is also observed bound at the active site. This work provides insights into the molecular basis of hPL kinase inhibition and may provide a working hypothesis to quickly screen or identify neurotoxic drugs as potential hPL kinase inhibitors. Such adverse effects may be prevented by administration of an appropriate form of vitamin B₆, or provide clues of how to modify these drugs to help reduce their hPL kinase inhibitory effects.
Collapse
Affiliation(s)
- Amit K. Gandhi
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Jigar V. Desai
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Mohini S. Ghatge
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Martino L. di Salvo
- Dipartimento di Scienze Biochimiche and Istituto Pasteur – Fondazione Cenci Bolognetti, Sapienza Università di Roma, Roma, Italy
| | - Stefano Di Biase
- Dipartimento di Scienze Biochimiche and Istituto Pasteur – Fondazione Cenci Bolognetti, Sapienza Università di Roma, Roma, Italy
| | - Richmond Danso-Danquah
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Faik N. Musayev
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Roberto Contestabile
- Dipartimento di Scienze Biochimiche and Istituto Pasteur – Fondazione Cenci Bolognetti, Sapienza Università di Roma, Roma, Italy
| | - Verne Schirch
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Martin K. Safo
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
| |
Collapse
|
20
|
di Salvo ML, Contestabile R, Safo MK. Vitamin B6 salvage enzymes: Mechanism, structure and regulation. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2011; 1814:1597-608. [DOI: 10.1016/j.bbapap.2010.12.006] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 12/13/2010] [Indexed: 10/18/2022]
|
21
|
Musayev FN, di Salvo ML, Ko TP, Gandhi AK, Goswami A, Schirch V, Safo MK. Crystal Structure of human pyridoxal kinase: structural basis of M(+) and M(2+) activation. Protein Sci 2007; 16:2184-94. [PMID: 17766369 PMCID: PMC2204131 DOI: 10.1110/ps.073022107] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Pyridoxal kinase catalyzes the transfer of a phosphate group from ATP to the 5' alcohol of pyridoxine, pyridoxamine, and pyridoxal. In this work, kinetic studies were conducted to examine monovalent cation dependence of human pyridoxal kinase kinetic parameters. The results show that hPLK affinity for ATP and PL is increased manyfold in the presence of K(+) when compared to Na(+); however, the maximal activity of the Na(+) form of the enzyme is more than double the activity in the presence of K(+). Other monovalent cations, Li(+), Cs(+), and Rb(+) do not show significant activity. We have determined the crystal structure of hPLK in the unliganded form, and in complex with MgATP to 2.0 and 2.2 A resolution, respectively. Overall, the two structures show similar open conformation, and likely represent the catalytically idle state. The crystal structure of the MgATP complex also reveals Mg(2+) and Na(+) acting in tandem to anchor the ATP at the active site. Interestingly, the active site of hPLK acts as a sink to bind several molecules of MPD. The features of monovalent and divalent metal cation binding, active site structure, and vitamin B6 specificity are discussed in terms of the kinetic and structural studies, and are compared with those of the sheep and Escherichia coli enzymes.
Collapse
Affiliation(s)
- Faik N Musayev
- Department of Medicinal Chemistry, School of Pharmacy and Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia 23219, USA
| | | | | | | | | | | | | |
Collapse
|