Small proline-rich protein 2A

Also known as: 2-1, SPRR2A, P35326

Small proline-rich protein 2A (SPRR2A), also known as 2-1, is a gut-derived bactericidal peptide that selectively targets Gram-positive bacteria. Its mechanism of action involves electrostatic binding to negatively charged lipids on bacterial membranes, which induces membrane permeabilization and disruption, leading to bacterial cell death. This selectivity is attributed to the peptide's affinity for specific lipid compositions characteristic of Gram-positive bacterial envelopes. Current research, supported by 24 PubMed references, remains at an experimental stage. Key findings indicate that SPRR2A is expressed in intestinal epithelial cells and contributes to host defense by modulating the gut microbiome composition. Studies have demonstrated its efficacy against pathogenic Gram-positive bacteria such as *Enterococcus faecalis* and *Listeria monocytogenes*, while sparing commensal flora. The peptide's activity is pH-dependent and influenced by the presence of bile salts, suggesting a role in maintaining intestinal homeostasis. Clinically, SPRR2A holds potential as a narrow-spectrum antimicrobial agent for treating Gram-positive infections, particularly in the gastrointestinal tract. Its targeted mechanism may reduce collateral damage to the microbiome compared to broad-spectrum antibiotics. However, no clinical trials have been conducted, and therapeutic applications remain hypothetical pending further validation of safety, stability, and in vivo efficacy. For research purposes only — not medical advice.

Key data

Mechanism of action

Gut bactericidal protein that selectively kills Gram-positive bacteria by binding to negatively charged lipids on bacterial membranes, leading to bacterial membrane permeabilization and disruption (PubMed:34735226). Specifically binds lipids bearing negatively charged headgroups, such as phosphatidic acid, phosphatidylserine (PS), cardiolipin (CL), and phosphatidylinositol phosphates, but not to zwitterionic or neutral lipids (PubMed:34735226). Induced by type-2 cytokines in response to helminth infection and is required to protect against helminth-induced bacterial invasion of intestinal tissue (By similarity). May also be involved in the development of the cornified envelope of squamous epithelia; however, additional evidences are required to confirm this result in vivo (PubMed:8325635)

Research & studies

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