M41 ATCC12373 falls into class I GAS (Rakonjac et al.,
1995). M41-type GAS-bound HDL might not be disrupted because SOF is not expressed by this strain. Hence HDL binding might be disadvantageous to M41 GAS. In such case, the counter-protective INK 128 concentration mechanism used by GAS remains unknown. C176, via its V region, could also interact with LDL, whereas C176T (partial V region-truncated variant) still bound to LDL (data not shown), but did not bind HDL. These results suggest that the sites on Scl1 for binding to HDL and LDL may be different. Additionally, C176 could be used for the production of lipid-free serum because it can specifically absorb both LDL and HDL from plasma or serum. ApoAI and ApoAII are major apolipoproteins in HDL. In order to explore the sites of HDL interacting with rScl1, affinity chromatography assays were used to examine the interaction between C176 and purified recombinant ApoAI and ApoAII. However, C176 could bind to neither ApoAI nor ApoAII (data not shown). Purified ApoAI and ApoAII may have different Selleck Cyclopamine conformations from those of native ApoAI and ApoAII in complex with HDL and so the possibility that C176 can bind to HDL via ApoAI and ApoAII cannot be excluded completely. In summary, the V region of Scl1 derived from M41-type GAS could bind to purified and plasma HDL, and this binding may be mediated by a hydrophobic interaction. The HDL–Scl1 interaction may play Teicoplanin an important role during GAS
infection. We thank Y. Pang, S. Du, L.M. Li, and F. Huo for technical assistance. This work was supported by the start-up Grant K32615 from the Inner Mongolia Agricultural University (to R.H.) and in part by National Institutes of Health Grant AI50666 (to S.L.).
Y.G. and C.L. contributed equally to this work. “
“A monomeric hemolysin with a molecular mass of 29 kDa was isolated from fresh fruiting bodies of the split gill mushroom Schizophyllum commune. The hemolysin was purified by successive adsorption on DEAE-cellulose, carboxymethyl-cellulose and Q-Sepharose and finally gel filtration on Superdex 75. This demonstrated the N-terminal sequence ATNYNKCPGA, different from those of previously reported fungal and bacterial hemolysins. The hemolysin was stable up to 40 °C. Only partial activity remained at 50 and 60 °C. Activity was indiscernible at 70 °C. A pH of 6.0 was optimal for activity. The hemolytic activity was most potently inhibited by dithiothreitol, sucrose and raffinose, followed by cellobiose, maltose, rhamnose, inulin, lactose, fructose and inositol. The metal ions Cu2+, Mg2+, Zn2+, Al3+ and Fe3+ significantly, and Pb2+ to a lesser extent, curtailed the activity of the hemolysin. The hemolysin inhibited HIV-1 reverse transcriptase with an IC50 of 1.8 μM. Mushrooms produce a large number of biologically active proteins. Hemolysins (Berne et al., 2002), antifungal proteins (Lam & Ng, 2001), laccases (Giardina et al.