The Sulfolobicin Genes of Sulfolobus acidocaldariusEncode Novel Antimicrobial Proteins

Abstract

Crenarchaea, such as Sulfolobus acidocaldarius and Sulfolobus tokodaii, produce antimicrobial proteins called sulfolobicins. These antimicrobial proteins inhibit the growth of closely related species. Here we report the identification of the sulfolobicin-encoding genes in S. acidocaldarius. The active sulfolobicin comprises two proteins that are equipped with a classical signal sequence. These proteins are secreted by the cells and found to be membrane vesicle associated. Gene inactivation studies demonstrate that both proteins are required for the bacteriostatic antimicrobial activity. Sulfolobicins constitute a novel class of antimicrobial proteins without detectable homology to any other protein.

Antimicrobial peptides and proteins in the face of extremes: Lessons from archaeocins

“…Membrane vesicles are 50e200 nm extracellular spherical vesicles, formed by budding of the cytoplasmic membrane but with specific protein composition [58]. Recent studies suggest involvement of vesicles in cellecell communication, as they can transfer quorum-sensing agents, toxins, pathogenicity factors, DNA, and RNA [58,59]. Using a procedure involving ultracentrifugation, Ellen et al [59] purified membrane vesicles from Sulfolobus acidocaldarius DSM639 and Sulfolobus tokodaii DSM16993.…”

The saci_2123 gene of the hyperthermoacidophile Sulfolobus acidocaldarius encodes an ATP-binding cassette multidrug transporter

“…The expression of saci_2123 upon treatment of the cells with various toxic compounds was analyzed by real-time quantitative PCR (qPCR) as described (Ellen et al 2011). S. acidocaldarius MR31 was incubated in the presence or absence of sublethal concentrations of 2,4-dinitrophenol (DPN) and ethidium bromide (EtBr) for 2 or 4 h, whereupon total RNA was isolated with the TRIzol (Invitrogen) reagent, followed by additional DNase treatment.…”

Bacteriocins of Aquatic Microorganisms and Their Potential Applications in the Seafood Industry

“…2E). These two proteins are associated with membrane vesicles in the extracellular medium (Ellen et al, 2011). The gene organization of archaeocins is also unique.…”

“…Like many bacteriocins, they are thermostable and sensitive to protease treatment. Their mode of action is still unknown (Ellen et al, 2011).…”

“…E-Genetic organization of archaeocin gene cluster. Sulfolobicin is composed of SulA and SulB proteins, encoded by sulA and sulB genes (adapted from Ellen et al, 2011).…”