Structural and immunological characterization of a new nucleotidyltransferase-like antigen from Paracoccidioides brasiliensis.

Autor: Coitinho JB; Departamento de Ciências Fisiológicas, Centro de Ciências da Saúde, Universidade Federal do Espírito Santo, Vitória, ES 29043-900, Brazil., Costa MAF; Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil., Melo EM; Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil., Morais EA; Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil., de Andrade LGA; Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil., da Rocha AM; Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil., de Magalhães MTQ; Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil., Favaro DC; Instituto de Química, Universidade Estadual de Campinas, Campinas, SP 13083-970, Brazil., Bleicher L; Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil., Pedroso ERP; Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil., Goes AM; Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil; Departamento de Patologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil., Nagem RAP; Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil. Electronic address: nagem@icb.ufmg.br.
Jazyk: angličtina
Zdroj: Molecular immunology [Mol Immunol] 2019 Aug; Vol. 112, pp. 151-162. Date of Electronic Publication: 2019 May 17.
DOI: 10.1016/j.molimm.2019.04.028
Abstrakt: Pb27 antigen is an interesting alternative to immunological diagnosis of Paracoccidioidomycosis (PCM) and has demonstrated to be protective in experimental PCM. Its tertiary structure and possible function remained unknown till now. To study Pb27 at the atomic level, the recombinant protein was expressed in Escherichia coli BL21(DE3), purified, and its three-dimensional structure was solved by X-ray crystallography. Based on this structure, we performed a residue correlation analysis and in silico ligand search assays to address a possible biological function to Pb27. We identified Pb27 as a member of the extensive nucleotidyltransferase superfamily. The protein has an αβαβαβ topology with two domains (N- and C-terminal domains) and adopts a monomeric form as its biological unit in solution. Structural comparisons with similar members of the superfamily clearly indicate Pb27 C-terminal domain is singular and may play an important role in its biological function. Bioinformatics analysis suggested that Pb27 might bind to ATP and CTP. This suggestion is corroborated by the fact that a magnesium cation is coordinated by two aspartic acid residues present at the active site (between N- and C-terminal domains), as evidenced by X-ray diffraction data. Besides, NMR assays ( 1 H- 15 N HSQC spectra) confirmed the binding of CTP to Pb27, demonstrating for the first time an interaction between a nucleotide and this protein. Moreover, we evaluated the reactivity of sera from patients with Paracoccidioides brasiliensis infection against the recombinant form of Pb27 and showed that it was recognized by sera from infected and treated patients. Predicted B and T cell epitopes were synthesized and further evaluated against sera of PCM patients, providing information of the most reactive peptides in Pb27 primary structure which interact with specific Pb27 antibodies.
(Copyright © 2019 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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