The role of PGN hydrolases in the ability of Staphylococcus aureus to evade the host innate immune system

• Autor(a) principal: Marques, Patrícia Costinha
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/31308
• topic: Staphylococcus aureus; peptidoglycan; autolysins; Sle1; SAOUHSC_00671; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Química

Staphylococcus aureus is an important microorganism that can be found on the skin and mucous membranes of the human body. Despite its ability to colonize the human host, invasion of this pathogen into the host tissue can lead to severe health conditions. As current antibiotics become less effective in the combat to this pathogen, it becomes urgent to develop new strategies of treatment. Peptidoglycan is present in gram-negative and gram-positive bacteria alike, as a fundamental molecule for cell structure. It is a telltale molecule that betrays the presence of the bacteria when recognized by host innate immune receptors such as the PGRP proteins. In order to avoid detection, S. aureus uses different strategies to circumvent recognition of the PGN at its surface. It has been shown that Atl, a major autolysin of S. aureus, is able to trim the outermost fragments of peptidoglycan in order to prevent the binding of PGRPs. This project focused in studying the protein SAOUHSC_00671 from S. aureus NCTC 8324-5 strain, which belongs to the same protein family as SleI, a PGN hydrolase capable of trimming PGN fragments at the staphylococcal division septum. This project aimed purify the SAOUHSC_00671 protein and construct knock-out S. aureus mutants, which lack the coding sequence for SAOUHSC_00671.