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Neira JL, Palomino-Schätzlein M. Folding of the nascent polypeptide chain of a histidine phosphocarrier protein in vitro. Arch Biochem Biophys 2023; 736:109538. [PMID: 36738980 DOI: 10.1016/j.abb.2023.109538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/28/2023] [Accepted: 02/01/2023] [Indexed: 02/05/2023]
Abstract
The phosphotransferase system (PTS), a metabolic pathway formed by five proteins, modulates the use of sugars in bacteria. The second protein in the chain is the histidine phosphocarrier, HPr, with the binding site at His15. The HPr kinase/phosphorylase (HPrK/P), involved in the bacterial use of carbon sources, phosphorylates HPr at Ser46, and it binds at its binding site. The regulator of sigma D protein (Rsd) also binds to HPr at His15. We have designed fragments of HPr, growing from its N-terminus and containing the His15. In this work, we obtained three fragments, HPr38, HPr58 and HPr70, comprising the first thirty-eight, fifty-eight and seventy residues of HPr, respectively. All fragments were mainly disordered, with evidence of a weak native-like, helical population around the binding site, as shown by fluorescence, far-ultraviolet circular dichroism, size exclusion chromatography and nuclear magnetic resonance. Although HPr38, HPr58 and HPr70 were disordered, they could bind to: (i) the N-terminal domain of first protein of the PTS, EIN; (ii) Rsd; and, (iii) HPrK/P, as shown by fluorescence and biolayer interferometry (BLI). The association constants for each protein to any of the fragments were in the low micromolar range, within the same range than those measured in the binding of HPr to each protein. Then, although acquisition of stable, native-like secondary and tertiary structures occurred at the last residues of the polypeptide, the ability to bind protein partners happened much earlier in the growing chain. Binding was related to the presence of the native-like structure around His15.
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Affiliation(s)
- José L Neira
- IDIBE, Universidad Miguel Hernández, 03202, Elche, Alicante, Spain; Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Joint Units IQFR-CSIC-BIFI and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018, Zaragoza, Spain.
| | - Martina Palomino-Schätzlein
- ProtoQSAR SL, CEEI-Valencia, Parque Tecnológico de Valencia, Av. Benjamin Franklin 12 (Dep. 8), 46980, Paterna, Valencia, Spain
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2
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Neira JL, Palomino-Schätzlein M, Hurtado-Gómez E, Ortore MG, Falcó A. An N-terminal half fragment of the histidine phosphocarrier protein, HPr, is disordered but binds to HPr partners and shows antibacterial properties. Biochim Biophys Acta Gen Subj 2021; 1865:130015. [PMID: 34537288 DOI: 10.1016/j.bbagen.2021.130015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/26/2021] [Accepted: 09/15/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND The phosphotransferase system (PTS) modulates the preferential use of sugars in bacteria. It is formed by a protein cascade in which the first two proteins are general (namely enzyme I, EI, and the histidine phosphocarrier protein, HPr) and the others are sugar-specific permeases; the active site of HPr is His15. The HPr kinase/phosphorylase (HPrK/P), involved in the use of carbon sources in Gram-positive, phopshorylates HPr at a serine. The regulator of sigma D protein (Rsd) also binds to HPr. We are designing specific fragments of HPr, which can be used to interfere with those protein-protein interactions (PPIs), where the intact HPr intervenes. METHODS We obtained a fragment (HPr48) comprising the first forty-eight residues of HPr. HPr48 was disordered as shown by fluorescence, far-ultraviolet (UV) circular dichroism (CD), small angle X-ray scattering (SAXS) and nuclear magnetic resonance (NMR). RESULTS Secondary structure propensities, from the assigned backbone nuclei, further support the unfolded nature of the fragment. However, HPr48 was capable of binding to: (i) the N-terminal region of EI, EIN; (ii) the intact Rsd; and, (iii) HPrK/P, as shown by fluorescence, far-UV CD, NMR and biolayer interferometry (BLI). The association constants for each protein, as measured by fluorescence and BLI, were in the order of the low micromolar range, similar to those measured between the intact HPr and each of the other macromolecules. CONCLUSIONS Although HPr48 is forty-eight-residue long, it assisted antibiotics to exert antimicrobial activity. GENERAL SIGNIFICANCE HPr48 could be used as a lead compound in the development of new antibiotics, or, alternatively, to improve the efficiency of existing ones.
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Affiliation(s)
- José L Neira
- IDIBE, Universidad Miguel Hernández, 03202, Elche (Alicante), Spain; Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain.
| | | | | | - María G Ortore
- Dipartimento DiSVA, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
| | - Alberto Falcó
- IDIBE, Universidad Miguel Hernández, 03202, Elche (Alicante), Spain.
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3
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Residual Helicity at the Active Site of the Histidine Phosphocarrier, HPr, Modulates Binding Affinity to Its Natural Partners. Int J Mol Sci 2021; 22:ijms221910805. [PMID: 34639146 PMCID: PMC8509676 DOI: 10.3390/ijms221910805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/01/2021] [Accepted: 10/02/2021] [Indexed: 11/16/2022] Open
Abstract
The phosphoenolpyruvate-dependent phosphotransferase system (PTS) modulates the preferential use of sugars in bacteria. The first proteins in the cascade are common to all organisms (EI and HPr). The active site of HPr involves a histidine (His15) located immediately before the beginning of the first α-helix. The regulator of sigma D (Rsd) protein also binds to HPr. The region of HPr comprising residues Gly9-Ala30 (HPr9–30), involving the first α-helix (Ala16-Thr27) and the preceding active site loop, binds to both the N-terminal region of EI and intact Rsd. HPr9–30 is mainly disordered. We attempted to improve the affinity of HPr9–30 to both proteins by mutating its sequence to increase its helicity. We designed peptides that led to a marginally larger population in solution of the helical structure of HPr9–30. Molecular simulations also suggested a modest increment in the helical population of mutants, when compared to the wild-type. The mutants, however, were bound with a less favorable affinity than the wild-type to both the N-terminal of EI (EIN) or Rsd, as tested by isothermal titration calorimetry and fluorescence. Furthermore, mutants showed lower antibacterial properties against Staphylococcus aureus than the wild-type peptide. Therefore, we concluded that in HPr, a compromise between binding to its partners and residual structure at the active site must exist to carry out its function.
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4
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Neira JL, Hornos F, Cozza C, Cámara-Artigas A, Abián O, Velázquez-Campoy A. The histidine phosphocarrier protein, HPr, binds to the highly thermostable regulator of sigma D protein, Rsd, and its isolated helical fragments. Arch Biochem Biophys 2017; 639:26-37. [PMID: 29288053 DOI: 10.1016/j.abb.2017.12.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 12/19/2017] [Accepted: 12/21/2017] [Indexed: 02/06/2023]
Abstract
The phosphotransferase system (PTS) controls the preferential use of sugars in bacteria and it is also involved in other processes, such as chemotaxis. It is formed by a protein cascade in which the first two proteins are general (namely, EI and HPr) and the others are sugar-specific permeases. The Rsd protein binds specifically to the RNA polymerase (RNAP) σ70 factor. We first characterized the conformational stability of Escherichia coli Rsd. And second, we delineated the binding regions of Streptomyces coelicolor, HPrsc, and E. coli Rsd, by using fragments derived from each protein. To that end, we used several biophysical probes, namely, fluorescence, CD, NMR, ITC and BLI. Rsd had a free energy of unfolding of 15 kcal mol-1 at 25 °C, and a thermal denaturation midpoint of 103 °C at pH 6.5. The affinity between Rsd and HPrsc was 2 μM. Interestingly enough, the isolated helical-peptides, comprising the third (RsdH3) and fourth (RsdH4) Rsd helices, also interacted with HPrsc in a specific manner, and with affinities similar to that of the whole Rsd. Moreover, the isolated peptide of HPrsc, HPr9-30, comprising the active site, His15, also was bound to intact Rsd with similar affinity. Therefore, binding between Rsd and HPrsc was modulated by the two helices H3 and H4 of Rsd, and the regions around the active site of HPrsc. This implies that specific fragments of Rsd and HPrsc can be used to interfere with other protein-protein interactions (PPIs) of each other protein.
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Affiliation(s)
- José L Neira
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche, Alicante, Spain; Instituto de Biocomputación y Física de Sistemas Complejos, Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, Spain.
| | - Felipe Hornos
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche, Alicante, Spain
| | - Concetta Cozza
- Molecular Biophysics Laboratory, Department of Physics, University of Calabria, Rende, Italy
| | - Ana Cámara-Artigas
- Department of Chemistry and Physics, Research Centre CIAIMBITAL, University of Almería- ceiA3, Almería, Spain
| | - Olga Abián
- Instituto de Biocomputación y Física de Sistemas Complejos, Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, Spain; Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, Spain; Aragon Institute for Health Research (IIS Aragon), Zaragoza, Spain; Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), Madrid, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain
| | - Adrián Velázquez-Campoy
- Instituto de Biocomputación y Física de Sistemas Complejos, Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, Spain; Aragon Institute for Health Research (IIS Aragon), Zaragoza, Spain; Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), Madrid, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain; Fundación ARAID, Diputación General de Aragón, Zaragoza, Spain.
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5
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Doménech R, Hernández-Cifre JG, Bacarizo J, Díez-Peña AI, Martínez-Rodríguez S, Cavasotto CN, de la Torre JG, Cámara-Artigás A, Velázquez-Campoy A, Neira JL. The histidine-phosphocarrier protein of the phosphoenolpyruvate: sugar phosphotransferase system of Bacillus sphaericus self-associates. PLoS One 2013; 8:e69307. [PMID: 23922699 PMCID: PMC3724859 DOI: 10.1371/journal.pone.0069307] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 06/12/2013] [Indexed: 12/12/2022] Open
Abstract
The phosphotransferase system (PTS) is involved in the use of carbon sources in bacteria. Bacillus sphaericus, a bacterium with the ability to produce insecticidal proteins, is unable to use hexoses and pentoses as the sole carbon source, but it has ptsHI genes encoding the two general proteins of the PTS: enzyme I (EI) and the histidine phosphocarrier (HPr). In this work, we describe the biophysical and structural properties of HPr from B. sphaericus, HPrbs, and its affinity towards EI of other species to find out whether there is inter-species binding. Conversely to what happens to other members of the HPr family, HPrbs forms several self-associated species. The conformational stability of the protein is low, and it unfolds irreversibly during heating. The protein binds to the N-terminal domain of EI from Streptomyces coelicolor, EINsc, with a higher affinity than that of the natural partner of EINsc, HPrsc. Modelling of the complex between EINsc and HPrbs suggests that binding occurs similarly to that observed in other HPr species. We discuss the functional implications of the oligomeric states of HPrbs for the glycolytic activity of B. sphaericus, as well as a strategy to inhibit binding between HPrsc and EINsc.
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Affiliation(s)
- Rosa Doménech
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche (Alicante), Spain
| | | | - Julio Bacarizo
- Departamento de Química y Física, Campus de Excelencia Internacional Agroalimentario, Universidad de Almería, Almería, Spain
| | - Ana I. Díez-Peña
- Departamento de Química Física, Universidad de Murcia, Murcia, Spain
| | - Sergio Martínez-Rodríguez
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche (Alicante), Spain
- Departamento de Química y Física, Campus de Excelencia Internacional Agroalimentario, Universidad de Almería, Almería, Spain
| | - Claudio N. Cavasotto
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET- Partner Institute of the Max Planck Society, Buenos Aires, Argentina
| | | | - Ana Cámara-Artigás
- Departamento de Química y Física, Campus de Excelencia Internacional Agroalimentario, Universidad de Almería, Almería, Spain
| | - Adrián Velázquez-Campoy
- Instituto de Biocomputación y Física de Sistemas Complejos, Unidad Asociada IQFR-CSIC-BIFI, Universidad de Zaragoza, Zaragoza, Spain
- Fundación ARAID, Diputación General de Aragón, Zaragoza, Spain
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain
| | - José L. Neira
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche (Alicante), Spain
- Instituto de Biocomputación y Física de Sistemas Complejos, Unidad Asociada IQFR-CSIC-BIFI, Universidad de Zaragoza, Zaragoza, Spain
- * E-mail:
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6
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Doménech R, Martínez-Gómez AI, Aguado-Llera D, Martínez-Rodríguez S, Clemente-Jiménez JM, Velázquez-Campoy A, Neira JL. Stability and binding of the phosphorylated species of the N-terminal domain of enzyme I and the histidine phosphocarrier protein from the Streptomyces coelicolor phosphoenolpyruvate:sugar phosphotransferase system. Arch Biochem Biophys 2012; 526:44-53. [PMID: 22809892 DOI: 10.1016/j.abb.2012.07.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 07/06/2012] [Accepted: 07/08/2012] [Indexed: 11/26/2022]
Abstract
The phosphotransferase system (PTS) is involved in the use of carbon sources in bacteria. It is formed by two general proteins: enzyme I (EI) and the histidine phosphocarrier (HPr), and various sugar-specific permeases. EI is formed by two domains, with the N-terminal domain (EIN) being responsible for the binding to HPr. In low-G+C Gram-positive bacteria, HPr becomes phosphorylated not only by phosphoenolpyruvate (PEP) at the active-site histidine, but also by ATP at a serine. In this work, we have characterized: (i) the stability and binding affinities between the active-site-histidine phosphorylated species of HPr and the EIN from Streptomyces coelicolor; and (ii) the stability and binding affinities of the species involving the phosphorylation at the regulatory serine of HPr(sc). Our results show that the phosphorylated active-site species of both proteins are less stable than the unphosphorylated counterparts. Conversely, the Hpr-S47D, which mimics phosphorylation at the regulatory serine, is more stable than wild-type HPr(sc) due to helical N-capping effects, as suggested by the modeled structure of the protein. Binding among the phosphorylated and unphosphorylated species is always entropically driven, but the affinity and the enthalpy vary widely.
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Affiliation(s)
- Rosa Doménech
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche (Alicante), Spain
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7
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Doménech R, Martínez-Rodríguez S, Velázquez-Campoy A, Neira JL. Peptides as Inhibitors of the First Phosphorylation Step of the Streptomyces coelicolor Phosphoenolpyruvate: Sugar Phosphotransferase System. Biochemistry 2012; 51:7393-402. [DOI: 10.1021/bi3010494] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Rosa Doménech
- Instituto de Biología
Molecular y Celular, Universidad Miguel Hernández, Elche (Alicante), Spain
| | - Sergio Martínez-Rodríguez
- Departamento de Química-Física,
Bioquímica y Química Inorgánica, Universidad de Almería, Almería, Spain
| | - Adrián Velázquez-Campoy
- Instituto de Biocomputación
y Física de Sistemas Complejos (BIFI), Unidad Asociada IQFR-BIFI, Universidad de Zaragoza, Zaragoza, Spain
- Fundación ARAID, Diputación General de Aragón, Zaragoza,
Spain
- Departamento de Bioquímica
y Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain
| | - José L. Neira
- Instituto de Biología
Molecular y Celular, Universidad Miguel Hernández, Elche (Alicante), Spain
- Instituto de Biocomputación
y Física de Sistemas Complejos (BIFI), Unidad Asociada IQFR-BIFI, Universidad de Zaragoza, Zaragoza, Spain
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8
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Nothaft H, Rigali S, Boomsma B, Swiatek M, McDowall KJ, van Wezel GP, Titgemeyer F. The permease gene nagE2 is the key to N-acetylglucosamine sensing and utilization in Streptomyces coelicolor and is subject to multi-level control. Mol Microbiol 2010; 75:1133-44. [PMID: 20487300 DOI: 10.1111/j.1365-2958.2009.07020.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The availability of nutrients is a major determinant for the timing of morphogenesis and antibiotic production in the soil-dwelling bacterium Streptomyces coelicolor. Here we show that N-acetylglucosamine transport, the first step of an important nutrient signalling cascade, is mediated by the NagE2 permease of the phosphotransferase system, and that the activity of this permease is linked to nutritional control of development and antibiotic production. The permease serves as a high-affinity transporter for N-acetylglucosamine (K(m) of 2.6 microM). The permease complex was reconstituted with individually purified components. This showed that uptake of N-acetylglucosamine requires a phosphoryl group transfer from phosphoenolpyruvate via the phosphotransferases EI, HPr and IIA(Crr) to NagF, which in turn phosphorylates N-acetylglucosamine during transport. Transcription of the nagF and nagE2 genes is induced by N-acetylglucosamine. Nutrient signalling by N-acetylglucosamine that triggers the onset of development was abolished in the nagE2 and nagF mutants. nagE2 is subject to multi-level control by the global transcription factor DasR and the activator AtrA that also stimulates genes for antibiotic actinorhodin biosynthesis. Hence, it is apparent that streptomycetes tightly control the nutritional state in a complex manner to ensure the correct timing for the developmental programme.
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Affiliation(s)
- Harald Nothaft
- Department of Biological Sciences and the Alberta Ingenuity Centre for Carbohydrate Science, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
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9
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Romero-Beviar M, Martínez-Rodríguez S, Prieto J, Goormaghtigh E, Ariz U, Martínez-Chantar MDLL, Gómez J, Neira JL. The N-terminal domain of the enzyme I is a monomeric well-folded protein with a low conformational stability and residual structure in the unfolded state. Protein Eng Des Sel 2010; 23:729-42. [PMID: 20630900 DOI: 10.1093/protein/gzq045] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The bacterial phosphoenolpyruvate-dependent sugar phosphotransferase system is a multiprotein complex that phosphorylates and, concomitantly, transports carbohydrates across the membrane into the cell. The first protein of the cascade is a multidomain protein so-called enzyme I (EI). The N-terminal domain of EI from Streptomyces coelicolor, EIN(sc), responsible for the binding to the second protein in the cascade (the histidine phosphocarrier, HPr), was cloned and successfully expressed and purified. We have previously shown that EI(sc) binds to HPr(sc) with smaller affinity than other members of the EI and HPr families [Hurtado-Gómez et al. (2008) Biophys. J., 95, 1336-1348]. We think that the study of the isolated binding HPr(sc) domain, that is EIN(sc), could shed light on the small affinity value measured. Therefore, in this work we present a detailed description of the structural features of the EIN domain, as a first step towards a complete characterization of the molecular recognition process between the two proteins. We show that EIN(sc) is a folded protein, with alpha-helix and beta-sheet structures and also random-coil conformations, as shown by circular dichroism (CD), FTIR and NMR spectroscopies. The acquisition of secondary and tertiary structures, and the burial of hydrophobic regions, occurred concomitantly at acidic pHs, but at very low pH, the domain acquired a molten-globule conformation. The EIN(sc) protein was not very stable, with an apparent conformational free energy change upon unfolding, DeltaG, of 4.1 +/- 0.4 kcal mol(-1), which was pH independent in the range explored (from pH 6.0 to 8.5). The thermal denaturation midpoint, which was also pH invariant, was similar to that measured in the isolated intact EI(sc). Although EIN(sc) shows thermal- and chemical denaturations that seems to follow a two-state mechanism, there is evidence of residual structure in the chemical and thermally unfolded states, as indicated by differential scanning calorimetry and CD measurements.
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Affiliation(s)
- Manuel Romero-Beviar
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Avda. del Ferrocarril s/n, 03202 Alicante, Elche, Spain
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10
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Defining the epitope region of a peptide from the Streptomyces coelicolor phosphoenolpyruvate:sugar phosphotransferase system able to bind to the enzyme I. Biophys J 2008; 95:1336-48. [PMID: 18456829 DOI: 10.1529/biophysj.107.126664] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The bacterial PEP:sugar PTS consists of a cascade of several proteins involved in the uptake and phosphorylation of carbohydrates, and in signal transduction pathways. Its uniqueness in bacteria makes the PTS a target for new antibacterial drugs. These drugs can be obtained from peptides or protein fragments able to interfere with the first reaction of the protein cascade: the phosphorylation of the HPr by the first enzyme, the so-called enzyme EI. To that end, we designed a peptide, HPr(9-30), spanning residues 9 to 30 of the intact HPr protein, containing the active site histidine (His-15) and the first alpha-helix of HPr of Streptomyces coelicolor, HPr(sc). By using fluorescence and circular dichroism, we first determined qualitatively that HPr(sc) and HPr(9-30) did bind to EI(sc), the enzyme EI from S. coelicolor. Then, we determined quantitatively the binding affinities of HPr(9-30) and HPr(sc) for EI(sc) by using ITC and STD-NMR. The STD-NMR experiments indicate that the epitope region of HPr(9-30) was formed by residues Leu-14, His-15, Ile-21, and Val-23. The binding reaction between EI(sc) and HPr(sc) is enthalpy driven and in other species is entropy driven; further, the affinity of HPr(sc) for EI(sc) was smaller than in other species. However, the affinity of HPr(9-30) for EI(sc) was only moderately lower than that of EI(sc) for HPr(sc), suggesting that this peptide could be considered a promising hit compound for designing new inhibitors against the PTS.
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11
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Poveda JA, Fernández-Ballester G, Prieto M, Neira JL. Dynamics of Tryptophan in the Histidine-Containing Phosphocarrier Protein of Streptomyces coelicolor: Evidence of Multistate Equilibrium Unfolding. Biochemistry 2007; 46:7252-60. [PMID: 17516658 DOI: 10.1021/bi7002923] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The nanosecond dynamics of the single tryptophan, Trp10, of HPr from Streptomyces coelicolor, HPrsc, has been monitored at different pHs. Time-resolved fluorescence methods and DOSY measurements have been used to map the compactness of the protein. At low pHs, where a molten globule-like species has been described, the correlation times from fluorescence showed an abrupt change as the pH was increased. When the protein was folded (above pH 4), two correlation times were observed, which remained practically constant up to pH 9.5. The long correlation time, around 7.5 ns, corresponds to the global rotational motion of the protein, since this value is in agreement with that determined theoretically from hydrodynamic measurements. The short correlation time, around 1.4 ns, must report on fast movements of the protein segment containing the tryptophan residue. On the other hand, fluorescence lifetimes showed the same abrupt change as the correlation times at low pH, but, in addition, a sigmoidal change with a pKa approximately 4.3 was also observed. On the basis of the modeled structure of HPrsc, this last transition could be due to the proximity of Glu12 to Trp10. The changes monitored by the fluorescence lifetimes agree with those observed previously by steady-state fluorescence, CD, and ANS binding experiments. Taken together, these data suggest a multistate equilibrium during folding of HPrsc starting from low pHs.
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Affiliation(s)
- José A Poveda
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, 03202 Elche (Alicante), Spain.
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12
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Horstmann N, Seidel G, Aung-Hilbrich LM, Hillen W. Residues His-15 and Arg-17 of HPr participate differently in catabolite signal processing via CcpA. J Biol Chem 2006; 282:1175-82. [PMID: 17085448 DOI: 10.1074/jbc.m605854200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The carbon catabolite control protein A (CcpA) senses the physiological state of the cell by binding several effectors and responds with differential regulation of many genes in Bacilli. HPr-Ser46-P or Crh-Ser46-P interact with CcpA and stimulate binding to catabolite responsive elements. In addition, the glycolytic intermediates fructose 1,6-bisphosphate (FBP) and glucose 6-phosphate (Glc-6-P) stimulate HPr-Ser46-P but not Crh-Ser46-P binding to CcpA. The mechanisms by which coeffector binding to CcpA is linked to differential gene expression are unclear. To address this question we mutated residues participating in the interaction between HPr-Ser46-P or Crh-Ser46-P and CcpA and analyzed their effects on CcpA binding and stimulation of cre binding by surface plasmon resonance. The HPrH15A and CcpAD297A mutations do not affect complex formation but abolish FBP and Glc-6-P stimulation. Likewise, the CrhQ15H mutant becomes sensitive to these glycolytic intermediates. Hence, the contact of HPrHis-15 to Asp-297 in CcpA is a determinant for HPr specific FBP and Glc-6-P stimulation. The HPrR17A and -K mutants are both strongly impaired in stimulation of CcpA binding to cre, but only HPrR17A is defect in binding to CcpA indicating that these residues affect allostery of CcpA. Mutations of the residues of CcpA, which contact Arg-17 of HPr, exhibit differential effects on regulation of catabolic genes. Taken together, His-15 of HPr processes sensing information, while Arg-17 is involved in determining the genetic output.
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Affiliation(s)
- Nicola Horstmann
- Lehrstuhl für Mikrobiologie, Universität Erlangen-Nürnberg, Staudtstrasse 5, 91058 Erlangen, Germany
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Hurtado-Gómez E, Fernández-Ballester G, Nothaft H, Gómez J, Titgemeyer F, Neira JL. Biophysical characterization of the enzyme I of the Streptomyces coelicolor phosphoenolpyruvate:sugar phosphotransferase system. Biophys J 2006; 90:4592-604. [PMID: 16581832 PMCID: PMC1471863 DOI: 10.1529/biophysj.105.076935] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The first protein in the bacterial phosphoenolpyruvate (PEP):sugar phosphotransferase system is the homodimeric 60-kDa enzyme I (EI), which autophosphorylates in the presence of PEP and Mg2+. The conformational stability and structure of the EI from Streptomyces coelicolor, EI(sc), were explored in the absence and in the presence of its effectors by using several biophysical probes (namely, fluorescence, far-ultraviolet circular dichroism, Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry) and computational approaches. The structure of EI(sc) was obtained by homology modeling of the isolated N- and C-terminal domains of other EI proteins. The experimental results indicate that at physiological pH, the dimeric EI(sc) had a well-folded structure; however, at low pH, EI(sc) showed a partially unfolded state with the features of a molten globule, as suggested by fluorescence, far-ultraviolet circular dichroism, FTIR, and 8-anilino-1-naphthalene-sulfonic acid binding. The thermal stability of EI(sc), in the absence of PEP and Mg2+, was maximal at pH 7. The presence of PEP and Mg2+ did not change substantially the secondary structure of the protein, as indicated by FTIR measurements. However, quenching experiments and proteolysis patterns suggest conformational changes in the presence of PEP; furthermore, the thermal stability of EI(sc) was modified depending on the effector added. Our approach suggests that thermodynamical analysis might reveal subtle conformational changes.
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Hurtado-Gómez E, Barrera FN, Neira JL. Structure and conformational stability of the enzyme I of Streptomyces coelicolor explored by FTIR and circular dichroism. Biophys Chem 2004; 115:229-33. [PMID: 15752610 DOI: 10.1016/j.bpc.2004.12.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2004] [Revised: 11/05/2004] [Accepted: 12/10/2004] [Indexed: 10/26/2022]
Abstract
The bacterial phosphoenolpyruvate (PEP): sugar phosphotransferase system (PTS), formed by a cascade of several proteins, couples the translocation and phosphorylation of specific sugars across cell membranes. The structure and thermal stability of the first protein (enzyme I, EI) of the PTS in Streptomyces coelicolor is studied by using far-UV circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR) at pH 7.0. The deconvolution of FTIR spectra indicates that the protein is mainly composed by a 35% of alpha-helical structure and 30% of beta-sheet. The thermal denaturation curves, as followed by both techniques, show only a midpoint at 330 K. This thermal denaturation behaviour is different to that observed in other members of the EI family.
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Affiliation(s)
- Estefanía Hurtado-Gómez
- Instituto de Biología Molecular y Celular, Edificio Torregaitán, Universidad Miguel Hernández, Avda. del Ferrocarril s/n, 03202, Elche, Alicante, Spain
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Neira JL, Gómez J. The conformational stability of the Streptomyces coelicolor histidine-phosphocarrier protein. ACTA ACUST UNITED AC 2004; 271:2165-81. [PMID: 15153107 DOI: 10.1111/j.1432-1033.2004.4142.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Thermodynamic parameters describing the conformational stability of the histidine-containing phosphocarrier protein from Streptomyces coelicolor, scHPr, have been determined by steady-state fluorescence measurements of isothermal urea-denaturations, differential scanning calorimetry at different guanidinium hydrochloride concentrations and, independently, by far-UV circular dichroism measurements of isothermal urea-denaturations, and thermal denaturations at fixed urea concentrations. The equilibrium unfolding transitions are described adequately by the two-state model and they validate the linear free-energy extrapolation model, over the large temperature range explored, and the urea concentrations used. At moderate urea concentrations (from 2 to 3 m), scHPr undergoes both high- and low-temperature unfolding. The free-energy stability curves have been obtained for the whole temperature range and values of the thermodynamic parameters governing the heat- and cold-denaturation processes have been obtained. Cold-denaturation of the protein is the result of the combination of an unusually high heat capacity change (1.4 +/- 0.3 kcal.mol(-1).K(-1), at 0 m urea, being the average of the fluorescence, circular dichroism and differential scanning calorimetry measurements) and a fairly low enthalpy change upon unfolding at the midpoint temperature of heat-denaturation (59 +/- 4 kcal.mol(-1), the average of the fluorescence, circular dichroism and differential scanning calorimetry measurements). The changes in enthalpy (m(DeltaH(i) )), entropy (m(DeltaS(i) )) and heat capacity (m(DeltaC(pi) )), which occur upon preferential urea binding to the unfolded state vs. the folded state of the protein, have also been determined. The m(DeltaH(i) ) and the m(DeltaS(i) ) are negative at low temperatures, but as the temperature is increased, m(DeltaH(i) ) makes a less favourable contribution than m(DeltaS(i) ) to the change in free energy upon urea binding. The m(DeltaC(pi) ) is larger than those observed for other proteins; however, its contribution to the global heat capacity change upon unfolding is small.
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Affiliation(s)
- José L Neira
- Instituto de Biología Molecular y Celular, Edificio Torregaitán, Universidad Miguel Hernández, Avda. del Ferrocarril s/n, 03202 Elche (Alicante), Spain.
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