Serine-rich repeat proteins from gut microbes

Abstract

Serine-rich repeat proteins (SRRPs) have emerged as an important group of cell surface adhesins found in a growing number of Gram-positive bacteria. Studies focused on SRRPs from streptococci and staphylococci demonstrated that these proteins are O-glycosylated on serine or threonine residues and exported via an accessory secretion (aSec) system. In pathogens, these adhesins contribute to disease pathogenesis and represent therapeutic targets. Recently, the non-canonical aSec system has been identified in the genomes of gut microbes and characterization of their associated SRRPs is beginning to unfold, showing their role in mediating attachment and biofilm formation. Here we provide an update of the occurrence, structure, and function of SRRPs across bacteria, with emphasis on the molecular and biochemical properties of SRRPs from gut symbionts, particularly Lactobacilli. These emerging studies underscore the range of ligands recognized by these adhesins and the importance of SRRP glycosylation in the interaction of gut microbes with the host.

Why Blood Group A Individuals Are at Risk Whereas Blood Group O Individuals Might Be Protected from SARS-CoV-2 (COVID-19) Infection: A Hypothesis Regarding How the Virus Invades the Human Body via Abo(H) Blood Group-Determining Carbohydrates

“…The history of this hydrophilic amino acid and its essential involvement in the pathogenesis of SARS-CoV-2 strongly suggest that the binding between pathogen and host occurs via O-glycosylation. Although serine-rich repeat proteins (SRRPs) that are involved in the adhesion of different bacteria (Latousakis et al, 2020) to host cell carbohydrates via O-glycosylation have not yet been described for the pathogenesis of viral infections, such a mechanism might occur in the pathogenesis of SARS-CoV infections. Moreover, the inhibition of the TMPRSS2 enzyme or the blocking of serine mobilization, studied by Meyer et al (2013) in an E. coli infection, might be utilized by newer pharmaceuticals in future therapeutic strategies against SARS-CoV-2 (Wang et al, 2020).…”

Butanol Tolerance of Lactiplantibacillus plantarum: A Transcriptome Study

“…The serine-rich repeat proteins (SRRPs) are common on the surface of various lactobacilli such as Limosilactobacillus reuteri , but none of them have been found in the genome of L. plantarum [ 58 ]. Further studies will be needed to explain this curious pattern of tRNA-Ser expression in L. plantarum Ym1 under butanol stress.…”

Why blood group A individuals are at risk whereas blood group O individuals are protected from SARS-CoV-2 (COVID-19) infection: A hypothesis regarding how the virus invades the human body via ABO(H) blood group-determining carbohydrates

“…The history of this hydrophilic amino acid and its essential involvement in the pathogenesis of SARS-CoV-2 strongly suggest that the binding between pathogen and host occurs via O -glycosylation. Although serine-rich repeat proteins (SRRPs) that are involved in the adhesion of different bacteria ( Latousakis et al, 2020 ) to host cell carbohydrates via O -glycosylation have not yet been described for the pathogenesis of viral infections, such a mechanism might occur in the pathogenesis of SARS-CoV infections. Moreover, the inhibition of the TMPRSS2 enzyme or the blocking of serine mobilization could be therapeutic strategies against the influenza virus ( Meyer et al, 2013 ) and SARS-CoV-2 ( Wang et al, 2020 ).…”