Serine-rich repeat adhesin SrpA (SrpA) (SrpA)

Serine-rich repeat adhesin SrpA is a large, heavily O-glycosylated surface glycoprotein expressed by Streptococcus sanguinis, a primary colonizer of the human oral cavity and a leading cause of infective endocarditis [1, 10]. SrpA belongs to the family of serine-rich repeat proteins (SRRPs) and plays a pivotal role in bacterial pathogenesis by mediating the high-avidity attachment of S. sanguinis to human platelets [2, 13]. This interaction occurs through the binding of the SrpA sialoglycan-binding region (BR) to sialoglycans on the platelet membrane receptor glycoprotein Ib alpha (GPIbα) [1, 10]. By facilitating platelet-bacterial aggregation, SrpA promotes the formation of vegetations on damaged heart valves, a hallmark of endocarditis [7, 8]. While no drugs currently target SrpA in clinical practice, it is considered a high-priority therapeutic target for the development of anti-adhesion therapies [6, 15]. Such treatments aim to prevent the progression of endocarditis by blocking the initial attachment of the bacteria to the cardiovascular endothelium and circulating platelets [2, 13]. Research into small-molecule inhibitors and monoclonal antibodies targeting the SrpA binding domain is ongoing to provide alternatives to traditional antibiotics [10, 15].

Other names

Serine-rich protein ASrpA adhesinSialoglycan-binding adhesinSerine-rich repeat protein (SRRP)

Inhibition of bacterial adhesion to host platelets by competitively blocking the sialoglycan-binding region of the adhesin.