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

Publication date: August 2019Source: Molecular Immunology, Volume 112Author(s): Juliana B. Coitinho, Mariana A.F. Costa, Eliza M. Melo, Elis A. Morais, Lorena G.A. de Andrade, Aline M. da Rocha, Mariana T.Q. de Magalhães, Denize C. Favaro, Lucas Bleicher, Enio R.P. Pedroso, Alfredo M. Goes, Ronaldo A.P. NagemAbstractPb27 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...
Source: Molecular Immunology - Category: Allergy & Immunology Source Type: research