Data/hora: 10/06/2024 14:21:55

Provedor de dados: 	42	
País: 	Brazil	
Título: 	Conformational analysis of Pneumococcal Surface Antigen A (PsaA) upon zinc binding by fluorescence spectroscopy	
Autores: 	Bom,Ana Paula D. Ano; Corrêa,Izabella B.S.; Argondizzo,Ana Paula C.; Medeiros,Marco Alberto; Santos,Roger B. dos; Souza,Theo Luiz F. de; Silva Junior,José G. da.	
Data: 	2018-08-01	
Ano: 	2018	
Palavras-chave: 	Conformational analysis; RPsaA; Zinc; Stability; Streptococcus Pneumoniae.	
Resumo: 	ABSTRACT PsaA (pneumococcal surface antigen A) is a S. pneumoniae virulence factor that belongs to the metal transport system. The Manganese PsaA binding has been associated with oxidative stress resistance becoming a pivotal element in the bacteria virulence. It has been shown that Zinc inhibits the Manganese acquisition and promotes bacteria toxicity. We have performed a PsaA conformational analysis both in the presence (Zn-rPsaA) and in the absence of Zinc (free-rPsaA). We performed experiments in the presence of different Zinc concentrations to determine the metal minimum concentration which induced a conformational change. The protein in free and Zn-binding condition was also studied in pH ranging 2.6-8.0 and in temperature ranging 25oC-85oC. pH experiments showed a decrease of fluorescence intensity only in acidic medium. Analysis of the heat-induced denaturation demonstrated that Zinc-binding promoted an increase in melting temperature from 55oC (free-rPsaA) to 78.8oC (Zn-rPsaA) according to fluorescence measurements. In addition, the rPsaA stabilization by Zinc was verified through analysis of urea and guanidine hydrochloride denaturation. Data showed that Zinc promoted an increase in the rPsaA stability and its removal by EDTA can lead to a PsaA intermediate conformation. These findings can be considered in the development of vaccines containing PsaA as antigen.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652018000502299	
Editor: 	Academia Brasileira de Ciências	
Relação: 	10.1590/0001-3765201820170151	
Formato: 	text/html	
Fonte: 	Anais da Academia Brasileira de Ciências  v.90 n.2 suppl.1 2018	
Fonte: 	info:eu-repo/semantics/openAccess