The S-Layer Protein of Bacillus thuringiensis CTC Strain Forms Parasporal Crystals
苏云金芽胞杆菌CTC菌株的S-层蛋白可以形成伴胞晶体

Bacillus thuringiensis strain CTC forms ellipsoid crystals. Transmission electron microscope observation showed that CTC cells had a clear S-layer. It was found that CTC strain formed parasporal crystals during sporulation and preliminary structure of S-layer inside the cells. After the crystal protein encoding gene ctc was transformed into the crystal negative Bacillus thuringiensis strain BMB171, the transformats could also form crystals similar to those of strain CTC as observed under scanning electron microscope. SDS-PAGE showed that the molecular weight of crystal protein product in recombinant strain BMB171 was identical to that of strain CTC. It was concluded that the S-layer proteins of CTC strain can form parasporal crystals, along with previous results that both the N-terminal aminto acid sequence of crystal protein and the DNA sequence of the encoding gene ctc showed high homologous with those of S-layer proteins.