A 2S Albumin from the Seed Cake of Ricinus communis Inhibits Trypsin and Has Strong Antibacterial Activity against Human Pathogenic Bacteria

Abstract

Hospital-acquired infections caused by antibiotic-resistant bacteria threaten the lives of many citizens all over the world. Discovery of new agents to hinder bacterial development would have a significant impact on the treatment of infections. Here, the purification and characterization of Rc-2S-Alb, a protein that belongs to the 2S albumin family, from Ricinus communis seed cake, are reported. Rc-2S-Alb was purified after protein extraction with Tris-HCl buffer, pH 7.5, fractionation by ammonium sulfate (50-75%), and chromatography on Phenyl-Sepharose and DEAE-Sepharose. Rc-2S-Alb, a 75 kDa peptide, displays trypsin inhibitory activity and has high in vitro antibacterial activity against Bacillus subtilis, Klebsiella pneumonia, and Pseudomonas aeruginosa, which are important human pathogenic bacteria. Atomic force microscopy studies indicated that Rc-2S-Alb disrupts the bacterial membrane with loss of the cytoplasm content and ultimately bacterial death. Therefore, Rc-2S-Alb is a powerful candidate for the development of an alternative drug that may help reduce hospital-acquired infections.

Protein Structure Insights into the Bilayer Interactions of the Saposin-Like Domain of Solanum tuberosum Aspartic Protease

“…Additionally, the sole positive charge (bold underlined), shown to be essential for activity in the present study, is surrounded by multiple Gln or Asn residues at the C-terminus. Interestingly, this overall arrangement is shared with certain other plant defence-related proteins including the flocculating cationic peptide from Moringa oleifera seed shown to damage bacterial membranes via a membrane fusion mechanism 75 , and a 2S albumin from Ricinus communis which causes leakage of bacterial cells postulated to result from magainin-like pore formation 76 (see Table 1 ). A motif query (avoiding redundancy) of the RCSB Protein Data Bank for the H3 C-terminal 6-residue motif [N/Q]-[N/Q]-[N/Q]-[A/L/I/V]-[K/R]-[N/Q] yielded a total of just 28 proteins, all lipid-interacting or surface-active (see Supplementary Table S1 for a listing of these matches).…”

Anticandidal activity of synthetic peptides: Mechanism of action revealed by scanning electron and fluorescence microscopies and synergism effect with nystatin

“…Recently, our research group characterized and evaluated the antimicrobial activity of many SAMPs against bacteria and yeasts pathogenic to humans 13–15 . For example, Dias et al 14 reported that Rc Alb‐PepII (SLRGCC) is a small (637.77 Da), positively charged (+1), and slightly (pI 7.80) basic peptide with hydrophobicity of 50%, derived from an antimicrobial 2S albumin purified from Ricinus communis seed cake, 16 and a potent antimicrobial peptide against C. parapsilosis and Klebsiella pneumoniae . Lopes et al 15 reported that a synthetic peptide derived from a thaumatin protein induces apoptosis in C. albicans .…”

Antidermatophytic activity of synthetic peptides: Action mechanisms and clinical application as adjuvants to enhance the activity and decrease the toxicity of Griseofulvin

“…Trichophyton mentagrophytes microconidia were analysed by AFM, as previously described by Souza et al 20 The samples were treated with peptides, collected and washed as done for the SEM analysis. After that, the protocol for AFM was followed.…”