Purification and characterization of cell wall proteins of Listeria monocytogenes

Abstract

Two proteins were purified from Listeria monocytogenes cell wall using detergent extraction, Superose 6 gel chromatography. Mono Q cation-exchange chromatography and Superose 12 gel chromatography. Proteins were shown to form complexes of ca. 300 kDa and pI 4.7. These complexes could not be dissociated in 6 M urea, however, during SDS-PAGE 79 and 39 kDa monomers were formed. Immunoblot analysis showed that the proteins under investigation were common to all listerial strains tested, but were absent in strains of other bacteria. We propose that the proteins investigated here could serve as immunoserological markers for Listeria.

Close Packing of Listeria monocytogenes ActA, a Natively Unfolded Protein, Enhances F-actin Assembly without Dimerization

“…Our size exclusion data shows that monomeric ActA has a Stokes radius of 8.0 nm (Fig. 2), in agreement with previously published results (32,34). A Stokes radius of 8.0 nm corresponds to a globular protein of 710 kDa.…”

“…Analytical ultracentrifugation has demonstrated that ActA exists as a monomer in solution (20,32) with ambiguous results regarding higher order multimers (32). ActA has been shown to behave as an anomalously large species by gel filtration, suggesting that it may be an elongated molecule (32,34). Dimer formation has been reported for ActA (35) based on its ability to interact with itself in a yeast two-hybrid assay and on crosslinking in situ on the bacterial surface to a dimeric form but not to higher-order multimers.…”

Isolation and characterization of a Listeria monocytogenes mutant strain hyperproducing virulence factors

“…Next, we examined proteins of cell walls and supernatants of NG602 and the parental strain in Western immunoblotting with antiserums against listeriolysin O, PI‐PLC and metalloprotease. As a control we used a cell wall protein Lm79/39, the expression of which remains constant under conditions affecting virulence protein expression [12]. Elevation of production of PI‐PLC and metalloprotease by NG602 was revealed in supernatant of liquid culture (Fig.…”

Purification and characterization of a 58-kDa cell wall-associated protein from Listeria monocytogenes

“…For isolation of cell wall we used the method described earlier [2]. In brief, L. monocytogenes was grown in Brain Heart Infusion Broth (Difco, USA).…”

“…In a previous investigation we succeeded in purifying two proteins with molecular masses of 79 and 39 kDa. The proteins were common to all tested listerial strains and, thus, appeared to represent genus-wide markers of the bacterium [2]. The aim of the present study was the further characterization of cell-associated proteins of L. monocytogenes.…”