Resumo

Staphylococcus saprophyticus is a Gram-positive, coagulase-negative bacterium that causes genitourinary infections preferentially in women. Several factors related with the ability of adhesion, proliferation and infection in the human host are associated with the proteins presented in the pathogen cell surface. Furthermore, the surface antigenic proteins can be important target to vaccines and antibodies development, since the cell wall is the first barrier during contact with the host. The surface proteins include membrane proteins, lipoproteins, covalently attached cell wall proteins and noncovalently attached proteins. This work aims identify the Staphylococcus saprophyticus surface proteins by using a proteolytic shaving approach that cleaves surface-exposed protein domains. The peptides were obtained by trypsin digestion were reduced, alkylated and identified by nano-chromatography using a nanoACQUITY UPLC^TM system (Waters) coupled to a SYNAPT Q-TOF mass spectrometer (Waters). The homology analysis was performed using the software ProteinLynx 2.3 (Waters). The shaving standardization is still in progress. However, 11 proteins described as virulence factors and related to pathogenesis were identified until now. The localization prediction performed by PSORTb algorithm (version 3.0.2) was performed. Two proteins were predicted to be localized in the cell wall (uro adherence factor A and a putative uncharacterized protein); one protein is a probable membrane specie (lipoteichoic acid synthase), 4 proteins are predicted to be secreted (a probable transglycosylase isaA, bifunctional autolysin and 2 putative uncharacterized proteins) and the localization in the cell wall can reflect the protein transport to the extracellular medium. However, 4 proteins are not be predicted to be localized in the cell wall (60 kDa chaperonin, chaperone protein DnaK, pyruvate kinase and cell division protein ftsZ). These proteins are described acting in moonlight functions and can be secreted or localized in the cell wall by non-classical transport. The previous results identified proteins in the S. saprophyticus cell wall that can act as immunogenic proteins or can be related to adhesion and proliferation process. Further analysis by using polyclonal antibodies are under progress to elucidate the functions of the identified proteins. Financial Support: CNPq, CAPES and FAPEG.