S-layer protein A (SlpA)

S-layer protein A (SlpA) is the principal component of the S-layer (surface layer) in various Gram-positive bacteria, notably Clostridioides difficile and Lactobacillus acidophilus. The S-layer is a two-dimensional crystalline protein sheet that completely covers the cell surface, providing physical protection, structural stability, and mediating interactions with the host and environment[1][2][3]. In C. difficile, SlpA is post-translationally cleaved to generate high and low molecular weight subunits that reassemble at the cell surface, forming a tightly packed lattice with molecular sieving properties and acting as the main adhesion and immune evasion factor[2][3][5]. SlpA is essential for bacterial physiology, pathogenicity, and serves as a receptor for bacteriophages[4]. Targeting SlpA disrupts pathogen survival, underlies phage resistance/susceptibility, and offers a promising, but challenging, avenue for novel anti-infective therapeutics and vaccine design[5].

Other names

Surface layer protein AS-layer protein (strain-specific: C. difficile, L. acidophilus)SlpA S-layer protein

Inhibition or disruption of SlpA impairs pathogen adhesion, surface protection, and makes bacteria susceptible to immune defenses and phage attack - Antibodies or inhibitors can block assembly or expose bacteria to lysis