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Neira JL, Cámara-Artigas A, Hernández-Cifre JG, Ortore MG. The Histidine Phosphocarrier Kinase/Phosphorylase from Bacillus Subtilis Is an Oligomer in Solution with a High Thermal Stability. Int J Mol Sci 2021; 22:3231. [PMID: 33810099 PMCID: PMC8004850 DOI: 10.3390/ijms22063231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/12/2021] [Accepted: 03/15/2021] [Indexed: 01/25/2023] Open
Abstract
The histidine phosphocarrier protein (HPr) kinase/phosphorylase (HPrK/P) modulates the phosphorylation state of the HPr protein, and it is involved in the use of carbon sources by Gram-positive bacteria. Its X-ray structure, as concluded from crystals of proteins from several species, is a hexamer; however, there are no studies about its conformational stability, and how its structure is modified by the pH. We have embarked on the conformational characterization of HPrK/P of Bacillus subtilis (bsHPrK/P) in solution by using several spectroscopic (namely, fluorescence and circular dichroism (CD)) and biophysical techniques (namely, small-angle X-ray-scattering (SAXS) and dynamic light-scattering (DLS)). bsHPrK/P was mainly a hexamer in solution at pH 7.0, in the presence of phosphate. The protein had a high conformational stability, with an apparent thermal denaturation midpoint of ~70 °C, at pH 7.0, as monitored by fluorescence and CD. The protein was very pH-sensitive, precipitated between pH 3.5 and 6.5; below pH 3.5, it had a molten-globule-like conformation; and it acquired a native-like structure in a narrow pH range (between pH 7.0 and 8.0). Guanidinium hydrochloride (GdmCl) denaturation occurred through an oligomeric intermediate. On the other hand, urea denaturation occurred as a single transition, in the range of concentrations between 1.8 and 18 µM, as detected by far-UV CD and fluorescence.
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Affiliation(s)
- José L. Neira
- IDIBE, Universidad Miguel Hernández, 03202 Alicante, Spain
- Instituto de Biocomputación y Física de Sistemas Complejos, Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Ana Cámara-Artigas
- Departamento de Química y Física, Research Center CIAIMBITAL, Universidad de Almería- ceiA3, 04120 Almería, Spain;
| | - José Ginés Hernández-Cifre
- Departamento de Química Física, Facultad de Química, Campus de Espinardo, Universidad de Murcia, 30100 Murcia, Spain;
| | - María Grazia Ortore
- Dipartimento DiSVA, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy;
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Neira JL, Martínez-Rodríguez S, Hernández-Cifre JG, Cámara-Artigas A, Clemente P, Peralta S, Fernández-Moreno MÁ, Garesse R, García de la Torre J, Rizzuti B. Human COA3 Is an Oligomeric Highly Flexible Protein in Solution. Biochemistry 2016; 55:6209-6220. [PMID: 27791355 DOI: 10.1021/acs.biochem.6b00644] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The assembly of the protein complex of cytochrome c oxidase (COX), which participates in the mitochondrial respiratory chain, requires a large number of accessory proteins (the so-called assembly factors). Human COX assembly factor 3 (hCOA3), also known as MITRAC12 or coiled-coil domain-containing protein 56 (CCDC56), interacts with the first subunit protein of COX to form its catalytic core and promotes its assemblage with the other units. Therefore, hCOA3 is involved in COX biogenesis in humans and can be exploited as a drug target in patients with mitochondrial dysfunctions. However, to be considered a molecular target, its structure and conformational stability must first be elucidated. We have embarked on the description of such features by using spectroscopic and hydrodynamic techniques, in aqueous solution and in the presence of detergents, together with computational methods. Our results show that hCOA3 is an oligomeric protein, forming aggregates of different molecular masses in aqueous solution. Moreover, on the basis of fluorescence and circular dichroism results, the protein has (i) its unique tryptophan partially shielded from solvent and (ii) a relatively high percentage of secondary structure. However, this structure is highly flexible and does not involve hydrogen bonding. Experiments in the presence of detergents suggest a slightly higher content of nonrigid helical structure. Theoretical results, based on studies of the primary structure of the protein, further support the idea that hCOA3 is a disordered protein. We suggest that the flexibility of hCOA3 is crucial for its interaction with other proteins to favor mitochondrial protein translocation and assembly of proteins involved in the respiratory chain.
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Affiliation(s)
- José L Neira
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández , Elche, Alicante, Spain.,Biocomputation and Complex Systems Physics Institute , Zaragoza, Spain
| | | | | | - Ana Cámara-Artigas
- Department of Chemistry and Physics, University of Almería , Agrifood Campus of International Excellence (ceiA3), Almería, Spain
| | - Paula Clemente
- Departamento de Bioquímica-Instituto de Investigaciones Biomédicas "Alberto Sols", Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER) , Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital 12 de Octubre (i+12) , Madrid, Spain
| | - Susana Peralta
- Departamento de Bioquímica-Instituto de Investigaciones Biomédicas "Alberto Sols", Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER) , Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital 12 de Octubre (i+12) , Madrid, Spain
| | - Miguel Ángel Fernández-Moreno
- Departamento de Bioquímica-Instituto de Investigaciones Biomédicas "Alberto Sols", Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER) , Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital 12 de Octubre (i+12) , Madrid, Spain
| | - Rafael Garesse
- Departamento de Bioquímica-Instituto de Investigaciones Biomédicas "Alberto Sols", Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER) , Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital 12 de Octubre (i+12) , Madrid, Spain
| | | | - Bruno Rizzuti
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria , 87036 Rende, Italy
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Wang HM, Yu C. Investigating the refolding pathway of human acidic fibroblast growth factor (hFGF-1) from the residual structure(s) obtained by denatured-state hydrogen/deuterium exchange. Biophys J 2011; 100:154-64. [PMID: 21190667 DOI: 10.1016/j.bpj.2010.11.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 11/15/2010] [Accepted: 11/16/2010] [Indexed: 11/26/2022] Open
Abstract
Human fibroblast growth factor 1 (hFGF-1) consists of 12 anti-parallel β-strands arranged into a β-trefoil architecture. We directly measured hydrogen/deuterium exchange rates on the urea-denatured hFGF-1 to obtain the information with regard to the persistent residual interaction(s) in the unfolded hFGF-1. Thirty-eight residues whose heteronuclear single quantum coherence cross-peaks can be observed after exchange show higher protections than those predicted for the same residues in a random coil conformation, suggesting the existence of residual structure(s). The urea-denaturation of hFGF-1 tested by both circular dichroism and fluorescence spectroscopy indicated that the unfolding process is a cooperative two-state process and that the residual structures observed did not originate from the existence of a partially structured intermediate. The coincident disappearance of the native heteronuclear single quantum coherence cross-peaks during the urea-denaturation process suggests that the residual structures observed contain no nativelike interactions. The protected residues (fold ons) in the urea-denatured state are mostly those that exchange slowly in the native state H/D exchange. The distribution of these fold ons in the native structure of hFGF-1 suggests that the refolding starts by collisions between the residual structures (microdomains) between the β-strands VI and VII, and between the β-strands II and III, which appear to be two independent refolding coordinates during the refolding process.
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Affiliation(s)
- Han-Min Wang
- Department of Chemistry, National Tsing-Hua University, Hsin-Chu, Taiwan, Republic of China
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Dellarole M, Sánchez IE, de Prat Gay G. Thermodynamics of cooperative DNA recognition at a replication origin and transcription regulatory site. Biochemistry 2010; 49:10277-86. [PMID: 21047141 PMCID: PMC3091369 DOI: 10.1021/bi1014908] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
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Binding cooperativity guides the formation of protein−nucleic acid complexes, in particular those that are highly regulated such as replication origins and transcription sites. Using the DNA binding domain of the origin binding and transcriptional regulator protein E2 from human papillomavirus type 16 as model, and through isothermal titration calorimetry analysis, we determined a positive, entropy-driven cooperativity upon binding of the protein to its cognate tandem double E2 site. This cooperativity is associated with a change in DNA structure, where the overall B conformation is maintained. Two homologous E2 domains, those of HPV18 and HPV11, showed that the enthalpic−entropic components of the reaction and DNA deformation can diverge. Because the DNA binding helix is almost identical in the three domains, the differences must lie dispersed throughout this unique dimeric β-barrel fold. This is in surprising agreement with previous results for this domain, which revealed a strong coupling between global dynamics and DNA recognition.
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Affiliation(s)
- Mariano Dellarole
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-Conicet, Patricias Argentinas 435, Buenos Aires, Argentina
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Wetzler DE, Castaño EM, de Prat-Gay G. A quasi-spontaneous amyloid route in a DNA binding gene regulatory domain: The papillomavirus HPV16 E2 protein. Protein Sci 2007; 16:744-54. [PMID: 17384235 PMCID: PMC2203337 DOI: 10.1110/ps.062594007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The DNA binding domain of papillomavirus E2 proteins is at the center of the regulation of gene transcription and replication of the virus. Its unique fold consists of a beta-barrel domain that combines an eight-stranded dimeric beta-barrel core interface with two symmetrical DNA binding alpha-helices and other two helices, packed against the central barrel. Treatment with low amounts of trifluoroethanol readily leads to a mostly beta-sheet oligomeric species, with a loss of near-UV circular dichroism signal and increase in its ANS binding capacity, indicating that buried hydrophobic surfaces become accessible to the solvent. This species subsequently undergoes a slow transition into amyloid aggregates as determined by light scattering and Congo red and thioflavin T binding. Electron microscopy shows short amyloid fibers with a curly aspect as the end product. The amyloid route is completely prevented by addition of stoichiometrical amounts of specific DNA, strongly suggesting that unfolding of the DNA binding alpha-helix is required for the formation of the intermediate. The slow nature of this expanded beta-oligomeric species and the availability of several different conformational probes make it an excellent model for investigating amyloid mechanisms. The mild perturbation required for entering an amyloid route is indicative of a preexisting equilibrium. Oligomerization processes are required for the assembly of transcription initiation and DNA replication machineries, where proteins from different viruses must come together with host cell proteins. The E2 protein is a virus-encoded multifunctional master regulator that may exert one of its multiple functions through its ability to oligomerize.
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Mok KH, Nagashima T, Day IJ, Hore PJ, Dobson CM. Multiple subsets of side-chain packing in partially folded states of alpha-lactalbumins. Proc Natl Acad Sci U S A 2005; 102:8899-904. [PMID: 15956205 PMCID: PMC1157025 DOI: 10.1073/pnas.0500661102] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Indexed: 11/18/2022] Open
Abstract
Photochemically induced dynamic nuclear polarization NMR pulse-labeling techniques have been used to obtain detailed information about side-chain surface accessibilities in the partially folded (molten globule) states of bovine and human alpha-lactalbumin prepared under a variety of well defined conditions. Pulse labeling involves generating nuclear polarization in the partially folded state, rapidly refolding the protein within the NMR sample tube, then detecting the polarization in the well dispersed native-state spectrum. Differences in the solvent accessibility of specific side chains in the various molten globule states indicate that the hydrophobic clusters involved in stabilizing the alpha-lactalbumin fold can be formed from interactions between a variety of different hydrophobic residues in both native and non-native environments. The multiple subsets of hydrophobic clusters are likely to result from the existence of distinct but closely related local minima on the free-energy landscape of the protein and show that the fold and topology of a given protein may be formed from degenerate groups of side chains.
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Affiliation(s)
- K Hun Mok
- Department of Chemistry, Oxford Centre for Molecular Sciences, Central Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QH, United Kingdom
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