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Buschi E, Dell’Anno A, Tangherlini M, Candela M, Rampelli S, Turroni S, Palladino G, Esposito E, Martire ML, Musco L, Stefanni S, Munari C, Fiori J, Danovaro R, Corinaldesi C. Resistance to freezing conditions of endemic Antarctic polychaetes is enhanced by cryoprotective proteins produced by their microbiome. SCIENCE ADVANCES 2024; 10:eadk9117. [PMID: 38905343 PMCID: PMC11192080 DOI: 10.1126/sciadv.adk9117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 05/14/2024] [Indexed: 06/23/2024]
Abstract
The microbiome plays a key role in the health of all metazoans. Whether and how the microbiome favors the adaptation processes of organisms to extreme conditions, such as those of Antarctica, which are incompatible with most metazoans, is still unknown. We investigated the microbiome of three endemic and widespread species of Antarctic polychaetes: Leitoscoloplos geminus, Aphelochaeta palmeri, and Aglaophamus trissophyllus. We report here that these invertebrates contain a stable bacterial core dominated by Meiothermus and Anoxybacillus, equipped with a versatile genetic makeup and a unique portfolio of proteins useful for coping with extremely cold conditions as revealed by pangenomic and metaproteomic analyses. The close phylosymbiosis between Meiothermus and Anoxybacillus and these Antarctic polychaetes indicates a connection with their hosts that started in the past to support holobiont adaptation to the Antarctic Ocean. The wide suite of bacterial cryoprotective proteins found in Antarctic polychaetes may be useful for the development of nature-based biotechnological applications.
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Affiliation(s)
- Emanuela Buschi
- Department of Ecosustainable Marine Biotechnology, Stazione Zoologica “Anton Dohrn,” Fano Marine Centre, Fano, Italy
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Antonio Dell’Anno
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Michael Tangherlini
- Department of Research Infrastructures for Marine Biological Resources, Stazione Zoologica “Anton Dohrn,” Fano Marine Centre, Fano, Italy
| | - Marco Candela
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
- Fano Marine Center, the Inter-Institute Center for Research on Marine Biodiversity, Resources and Biotechnologies, Fano, Italy
| | - Simone Rampelli
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
- Fano Marine Center, the Inter-Institute Center for Research on Marine Biodiversity, Resources and Biotechnologies, Fano, Italy
| | - Silvia Turroni
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Giorgia Palladino
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
- Fano Marine Center, the Inter-Institute Center for Research on Marine Biodiversity, Resources and Biotechnologies, Fano, Italy
| | - Erika Esposito
- Department of Chemistry “G. Ciamician” Alma Mater Studiorum, University of Bologna, Bologna, Italy
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italia
| | - Marco Lo Martire
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Luigi Musco
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Lecce, Italy
| | - Sergio Stefanni
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica “Anton Dohrn,” Villa Comunale, Napoli, Italy
| | - Cristina Munari
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Ferrara, Italy
| | - Jessica Fiori
- Department of Chemistry “G. Ciamician” Alma Mater Studiorum, University of Bologna, Bologna, Italy
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italia
| | - Roberto Danovaro
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Cinzia Corinaldesi
- Department of Materials, Environmental Sciences and Urban Planning, Polytechnic University of Marche, Ancona, Italy
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Díaz-Pérez AL, Díaz-Pérez C, Gaona-García RY, Hernández-Santoyo A, Lázaro-Mixteco PE, Reyes-De La Cruz H, Campos-García J. Study of peripheral domains in structure-function of isocitrate lyase (ICL) from Pseudomonas aeruginosa. World J Microbiol Biotechnol 2023; 39:339. [PMID: 37821748 DOI: 10.1007/s11274-023-03768-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 09/15/2023] [Indexed: 10/13/2023]
Abstract
The capacity of Pseudomonas aeruginosa to assimilate nutrients is essential for niche colonization and contributes to its pathogenicity. Isocitrate lyase (ICL), the first enzyme of the glyoxylate cycle, redirects isocitrate from the tricarboxylic acid cycle to render glyoxylate and succinate. P. aeruginosa ICL (PaICL) is regarded as a virulence factor due to its role in carbon assimilation during infection. The AceA/ICL protein family shares the catalytic domain I, triosephosphate isomerase barrel (TIM-barrel). The carboxyl terminus of domain I is essential for Escherichia coli ICL (EcICL) of subfamily 1. PaICL, which belongs to subfamily 3, has domain II inserted at the periphery of domain I, which is believed to participate in enzyme oligomerization. In addition, PaICL has the α13-loop-α14 (extended motif), which protrudes from the enzyme core, being of unknown function. This study investigates the role of domain II, the extended motif, and the carboxyl-terminus (C-ICL) and amino-terminus (N-ICL) regions in the function of the PaICL enzyme, also as their involvement in the virulence of P. aeruginosa PAO1. Deletion of domain II and the extended motif results in enzyme inactivation and structural instability of the enzyme. The His6-tag fusion at the C-ICL protein produced a less efficient enzyme than fusion at the N-ICL, but without affecting the acetate assimilation or virulence. The PaICL homotetrameric structure of the enzyme was more stable in the N-His6-ICL than in the C-His6-ICL, suggesting that the C-terminus is critical for the ICL quaternary conformation. The ICL-mutant A39 complemented with the recombinant proteins N-His6-ICL or C-His6-ICL were more virulent than the WT PAO1 strain. The findings indicate that the domain II and the extended motif are essential for the ICL structure/function, and the C-terminus is involved in its quaternary structure conformation, confirming that in P. aeruginosa, the ICL is essential for acetate assimilation and virulence.
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Affiliation(s)
- Alma Laura Díaz-Pérez
- Lab. de Biotecnología Microbiana, Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edif. U-3, Ciudad Universitaria, 58030, Morelia, Mich., Mexico
| | - César Díaz-Pérez
- Facultad de Agrobiologia, Campus Celaya-Salvatierra, Universiad de Guanajuato, Guanajuato, Gto., Mexico
| | - Roxana Yughadi Gaona-García
- Lab. de Biotecnología Microbiana, Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edif. U-3, Ciudad Universitaria, 58030, Morelia, Mich., Mexico
| | - Alejandra Hernández-Santoyo
- Departamento de Química de Biomacromoléculas, Instituto de Química, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Pedro E Lázaro-Mixteco
- Facultad de Ingeniería Química, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich., Mexico
| | - Homero Reyes-De La Cruz
- Lab. de Biotecnología Microbiana, Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edif. U-3, Ciudad Universitaria, 58030, Morelia, Mich., Mexico
| | - Jesús Campos-García
- Lab. de Biotecnología Microbiana, Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edif. U-3, Ciudad Universitaria, 58030, Morelia, Mich., Mexico.
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3
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Janssen K, Claes F, Van de Velde D, Wehbi VL, Houben B, Lampi Y, Nys M, Khodaparast L, Khodaparast L, Louros N, van der Kant R, Verniers J, Garcia T, Ramakers M, Konstantoulea K, Maragkou K, Duran-Romaña R, Musteanu M, Barbacid M, Scorneaux B, Beirnaert E, Schymkowitz J, Rousseau F. Exploiting the intrinsic misfolding propensity of the KRAS oncoprotein. Proc Natl Acad Sci U S A 2023; 120:e2214921120. [PMID: 36812200 PMCID: PMC9992772 DOI: 10.1073/pnas.2214921120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 01/18/2023] [Indexed: 02/24/2023] Open
Abstract
Mutant KRAS is a major driver of oncogenesis in a multitude of cancers but remains a challenging target for classical small molecule drugs, motivating the exploration of alternative approaches. Here, we show that aggregation-prone regions (APRs) in the primary sequence of the oncoprotein constitute intrinsic vulnerabilities that can be exploited to misfold KRAS into protein aggregates. Conveniently, this propensity that is present in wild-type KRAS is increased in the common oncogenic mutations at positions 12 and 13. We show that synthetic peptides (Pept-ins™) derived from two distinct KRAS APRs could induce the misfolding and subsequent loss of function of oncogenic KRAS, both of recombinantly produced protein in solution, during cell-free translation and in cancer cells. The Pept-ins exerted antiproliferative activity against a range of mutant KRAS cell lines and abrogated tumor growth in a syngeneic lung adenocarcinoma mouse model driven by mutant KRAS G12V. These findings provide proof-of-concept that the intrinsic misfolding propensity of the KRAS oncoprotein can be exploited to cause its functional inactivation.
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Affiliation(s)
- Kobe Janssen
- Switch Laboratory, VIB-KU Leuven Center for Brain and Disease Research, 3000Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven3000, Leuven, Belgium
| | | | | | | | - Bert Houben
- Switch Laboratory, VIB-KU Leuven Center for Brain and Disease Research, 3000Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven3000, Leuven, Belgium
| | - Yulia Lampi
- Switch Laboratory, VIB-KU Leuven Center for Brain and Disease Research, 3000Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven3000, Leuven, Belgium
| | - Mieke Nys
- Switch Laboratory, VIB-KU Leuven Center for Brain and Disease Research, 3000Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven3000, Leuven, Belgium
| | - Laleh Khodaparast
- Switch Laboratory, VIB-KU Leuven Center for Brain and Disease Research, 3000Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven3000, Leuven, Belgium
| | - Ladan Khodaparast
- Switch Laboratory, VIB-KU Leuven Center for Brain and Disease Research, 3000Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven3000, Leuven, Belgium
| | - Nikolaos Louros
- Switch Laboratory, VIB-KU Leuven Center for Brain and Disease Research, 3000Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven3000, Leuven, Belgium
| | - Rob van der Kant
- Switch Laboratory, VIB-KU Leuven Center for Brain and Disease Research, 3000Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven3000, Leuven, Belgium
| | - Joffre Verniers
- Switch Laboratory, VIB-KU Leuven Center for Brain and Disease Research, 3000Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven3000, Leuven, Belgium
| | - Teresa Garcia
- Switch Laboratory, VIB-KU Leuven Center for Brain and Disease Research, 3000Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven3000, Leuven, Belgium
| | - Meine Ramakers
- Switch Laboratory, VIB-KU Leuven Center for Brain and Disease Research, 3000Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven3000, Leuven, Belgium
| | - Katerina Konstantoulea
- Switch Laboratory, VIB-KU Leuven Center for Brain and Disease Research, 3000Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven3000, Leuven, Belgium
| | - Katerina Maragkou
- Switch Laboratory, VIB-KU Leuven Center for Brain and Disease Research, 3000Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven3000, Leuven, Belgium
| | - Ramon Duran-Romaña
- Switch Laboratory, VIB-KU Leuven Center for Brain and Disease Research, 3000Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven3000, Leuven, Belgium
| | - Mónica Musteanu
- Experimental Oncology Group, Molecular Oncology Program, Centro Nacional de Investigaciones Oncológicas, Madrid28029, Spain
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, Complutense University, 28040Madrid, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Instituto de Salud Carlos III, Madrid28029, Spain
| | - Mariano Barbacid
- Experimental Oncology Group, Molecular Oncology Program, Centro Nacional de Investigaciones Oncológicas, Madrid28029, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Instituto de Salud Carlos III, Madrid28029, Spain
| | | | | | - Joost Schymkowitz
- Switch Laboratory, VIB-KU Leuven Center for Brain and Disease Research, 3000Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven3000, Leuven, Belgium
| | - Frederic Rousseau
- Switch Laboratory, VIB-KU Leuven Center for Brain and Disease Research, 3000Leuven, Belgium
- Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven3000, Leuven, Belgium
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Kamel S, Schollmeyer J, Kurreck A, Neubauer P. Optimization of Inclusion Body Formation and Purification in Multi-well Plates. Methods Mol Biol 2023; 2617:121-138. [PMID: 36656520 DOI: 10.1007/978-1-0716-2930-7_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Heterologous expression has long been used for the efficient production of proteins and enzymes as it offers significant advantages over purification of proteins from their native organisms. When first established, great efforts have been made to heterologously express proteins with high yields in the soluble fraction, hence, avoiding protein aggregation. In recent decades, however, it has been shown that the formation of aggregates (inclusion bodies; IBs) can be beneficial. To recover active protein, however, proteins should have been refolded from IBs after purification. The discovery that IBs themselves can also be active has revolutionized the entire protein production field. Therefore, several approaches have been described to generate catalytically active IBs during heterologous expression. Since several extrinsic and intrinsic factors such as protein structure and toxicity, pH and temperature of expression, and the used media might influence the formation of IBs, it is time and material consuming to use shake flask to examine and optimize different expression conditions. However, by using multi-well plates, it is possible to rapidly develop an efficient protocol for the expression of catalytically active IBs in a rational approach. The presented protocol was used for the heterologous expression of a 5'-adenosine monophosphate phosphorylase which forms catalytically active aggregates during expression in E. coli.
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Affiliation(s)
- Sarah Kamel
- Technische Universität Berlin, Institute of Biotechnology, Chair of Bioprocess Engineering, Berlin, Germany
| | - Julia Schollmeyer
- Technische Universität Berlin, Institute of Biotechnology, Chair of Bioprocess Engineering, Berlin, Germany
- BioNukleo GmbH, Berlin, Germany
| | | | - Peter Neubauer
- Technische Universität Berlin, Institute of Biotechnology, Chair of Bioprocess Engineering, Berlin, Germany.
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Kamel S, Walczak MC, Kaspar F, Westarp S, Neubauer P, Kurreck A. Thermostable adenosine 5'-monophosphate phosphorylase from Thermococcus kodakarensis forms catalytically active inclusion bodies. Sci Rep 2021; 11:16880. [PMID: 34413335 PMCID: PMC8376864 DOI: 10.1038/s41598-021-96073-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 08/04/2021] [Indexed: 11/24/2022] Open
Abstract
Catalytically active inclusion bodies (CatIBs) produced in Escherichia coli are an interesting but currently underexplored strategy for enzyme immobilization. They can be purified easily and used directly as stable and reusable heterogenous catalysts. However, very few examples of CatIBs that are naturally formed during heterologous expression have been reported so far. Previous studies have revealed that the adenosine 5′-monophosphate phosphorylase of Thermococcus kodakarensis (TkAMPpase) forms large soluble multimers with high thermal stability. Herein, we show that heat treatment of soluble protein from crude extract induces aggregation of active protein which phosphorolyse all natural 5′-mononucleotides. Additionally, inclusion bodies formed during the expression in E. coli were found to be similarly active with 2–6 folds higher specific activity compared to these heat-induced aggregates. Interestingly, differences in the substrate preference were observed. These results show that the recombinant thermostable TkAMPpase is one of rare examples of naturally formed CatIBs.
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Affiliation(s)
- Sarah Kamel
- Chair of Bioprocess Engineering, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Miriam C Walczak
- Chair of Bioprocess Engineering, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany.,BioNukleo GmbH, Ackerstraße 76, 13355, Berlin, Germany
| | - Felix Kaspar
- Chair of Bioprocess Engineering, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany.,BioNukleo GmbH, Ackerstraße 76, 13355, Berlin, Germany
| | - Sarah Westarp
- Chair of Bioprocess Engineering, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany.,BioNukleo GmbH, Ackerstraße 76, 13355, Berlin, Germany
| | - Peter Neubauer
- Chair of Bioprocess Engineering, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Anke Kurreck
- Chair of Bioprocess Engineering, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany. .,BioNukleo GmbH, Ackerstraße 76, 13355, Berlin, Germany.
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Dotsenko OI, Mischenko АМ, Taradina GV. Vibration influence on the O2-dependent processes activity in human erythrocytes. REGULATORY MECHANISMS IN BIOSYSTEMS 2021. [DOI: 10.15421/022162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The early signs of vibration effects on the human body are microcirculation and transcapillary metabolism disorders, accompanied by disruption of the supply to and utilization of oxygen in the tissues and organs. However, there are few experimental studies aimed at finding targets of vibration in cells and determining the action mechanism of vibration. In in vitro experiments, human erythrocytes in buffer solution were exposed to low-frequency vibration (frequency range 8–32 Hz, amplitudes 0.5–0.9 mm) for 3 hours. The dynamics of the accumulation of membrane-bound catalase and hemoglobin and the distribution of ligand hemoglobin in the membrane-bound fraction were studied as the indicators of functional activity of cells. The choice of these indicators is justified by the participation of catalase and hemoglobin in O2-dependent cellular reactions as a part of protein complexes. Since pО2 is a trigger of conformational transitions in the hemoglobin molecule, simultaneously with oxygen transport, hemoglobin signals to different metabolic systems about oxygen conditions in the environment. The studies revealed that in the conditions of vibration, the activity of membrane-associated catalase increased by 40–50% in the frequency range of 12–24 Hz (amplitude 0.5 ± 0.04 mm), by 20–30% in the amplitude of 0.9 mm, but after about 100–120 min exposure the enzyme activity decreased even below the control level. There was a dose-dependent accumulation of membrane-bound hemoglobin during exposure to vibration. In the membrane-bound fraction of hemoglobin, oxyhemoglobin had the highest content (60–80%), while the content of methemoglobin varied 5–20%. During vibrations in the frequency range 12–28 Hz, 0.5 mm, we recorded 10–30% increase in oxyhemoglobin. With increase in the vibration amplitude (0.9 mm) in the frequency range of 16–32 Hz, constant content of oxyhemoglobin was noted at the beginning of the experiment, which tended to decrease during the last exposure time. Frequency of 32 Hz caused increase in the deoxyhemoglobin content in the membrane-bound fraction. The content of methemoglobin (metHb) in erythrocytes significantly increased during exposure to the frequency range of 12–24 Hz, with the amplitude of 0.5 mm (1.3–2.4 times). During the exposure to frequencies of 28 and 32 Hz, we observed the transition of methemoglobin to hemichrome. The content of methemoglobin in the cells was lower and decreased at the end of the experiment when the vibration amplitude was 0.9 mm. In these experimental conditions, no increase in hemichrome content in the membrane-bound fraction was recorded. Therefore, the degree of binding of catalase and hemoglobin with the membrane of erythrocytes that were exposed to vibration and the changes in the content of ligand forms in the composition of membrane-bound hemoglobin are dose-dependent. Low-frequency vibration initiates O2-dependent processes in erythrocytes. Targets of such an influence are nanobubbles of dissolved air (babstons), retained on the surface of erythrocytes due to Coulomb interactions, capable of coagulation and increase in size under the action of vibration. At first, the consequences of these processes are increase in oxygen content in the surface of erythrocytes, and then decrease as a result of degassing. Thus, increase in oxygen content on the surface initiates redox reactions, whereas decrease in oxygen content leads to reconstruction of metabolic processes oriented at overcoming hypoxia.
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Purification and characterisation of the dimeric group 12 allergen from Blomia tropicalis heterologously expressed by Escherichia coli Top10F´. Mol Biol Rep 2021; 48:3405-3416. [PMID: 33914278 DOI: 10.1007/s11033-021-06361-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 04/16/2021] [Indexed: 10/21/2022]
Abstract
Successful research in the wide-ranging field of allergy is usually achieved by definition not only of physicochemical and immunological properties of natural, but also recombinant allergens. Blomia tropicalis mite is a well-known source for various groups of hypersensitivity-causing proteins. The goal of the present work was to produce, purify and characterise by in silico, biochemical and immunological methods the recombinant group-12 allergen of B. tropicalis. The recombinant Blo t 12 aggregation capacity as well as the affinity to antibodies from BALB/c immunised mice and B. tropicalis-sensitised human donors were investigated through in silico analyses, dynamic light scattering, SDS-PAGE, ELISA and Western blot. The presence of Blo t 12 within B. tropicalis extracts was also determined by ELISA and Western blot. High concentrations of dimeric rBlo t 12 were detected through SDS-PAGE next to other aggregates and the results were confirmed by data from DLS and Western blot. The YITVM peptide was predicted to be the most aggregation-prone region. The IgE-reactivity of rBlo t 12 was not completely abolished by aggregate formation but it was significantly decreased compared to rBlo t 5, or B. tropicalis extracts. Natural Blo t 12 may naturally dimerises, but it was detected in non-delipidified B. tropicalis extracts in low amounts. Given that this allergen may be a specific marker for B. tropicalis allergy, the recombinant Blo t 12 herein obtained is characterised as a mid-tier allergen in Brazilian atopic patients and may be useful for the improvement in precision allergy molecular diagnostic applications.
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