One of the six transmembrane domains of AgrC from Staphylococcus aureus ATCC 6538 (agr I type) which is closest with the process of transmembrane signal transduction in quorum sensing was selected as a receptor. This polypeptide was inserted into the artificial cell membrane by ultrasonic procedure, and the pattern of the vesicles was analyzed by transmission electron microscopy (TEM) and atomic force microscopy (AFM). It was found that the single shape of most vesicles (blank and embedded with peptide) was uniform sphere, and the diameter size is from 50 to 200 nm. Considering the impact of suspension pH, concentration and temperature factors to the stability of the embeded system, it is found that the system was the most stable under the following conditions: pH 7.0, temperature lower than 30 ℃, mole ratio of the polypeptide and N^＋C₅Ala2C₁₆ being 1∶100. Meanwhile, it is also discovered that polypeptide was capable of inserting into bilayer vesicles stably and positively to form embeded system by circular dichroism spectra and differential scanning calorimetry.

Key words: transmembrane transduction, Staphyloccocus aureus, AgrC, transmembrane insertion