Identification and purification of a calcium-binding protein from Bacillus subtilis

A Ca²⁺-binding protein was identified in Bacillus subtilis in the log phase of growth. The molecular mass of this protein is about 38 kDa as estimated by polyacrylamide gel electrophoresis in the presence of SDS and by gel filtration. The protein was found to be resistant 10 min at 65°C and was purified about 400 times, starting from heated crude extract, by conventional procedures. This novel protein is able to bind Ca²⁺ in the presence of an excess of MgCl₂ and KCl both in solution and after SDS gel electrophoresis and electrotransfer. Since an impairment of the Ca²⁺ intake, in Bacillus subtilis, results in an impairment of chemotactic behavior (Matsushita, T. et al (1988) FEBS lett. 236, 437-440), 38 kDa protein may be involved in the regulation of chemotaxis.