PROCEDURE FOR PREPARING A VARIANT OF THE SURFACE PROTECTING ANTIGEN OF ERYSIPELOTHRIX RHUSIOPATHIAE IN E. COLI.

摘要

A method for preparing a SpaA protein variant of the surface protective antigen of Erysipelothrix rhusiopathiae or in a reduced form thereof, the ΔSpaA protein, where at least about 1/3 of the C-terminus of the SpaA protein is suppressed, having said variant immunogenicity and being expressed in E. coli in the form of inclusion bodies, which comprises mutating a gene encoding said SpaA or ΔSpaA protein so that an amino acid substitution can be introduced into the amino acid sequence of said SpaA or ΔSpaA protein, allowing the resulting mutated gene to be expressed in E. coli, and selecting said variant that formed inclusion bodies among the expressed variants, wherein said amino acid substitution is one or a combination of more than one selected from the group consisting of (1) to (7) described below: (1) the 69 or amino acid of the N-terminus that encompasses the signal sequence is substituted by glyc ina; (2) the 154 or amino acid of the N-terminus that encompasses the signal sequence is substituted by glycine; (3) the 203 or amino acid of the N-terminus that encompasses the signal sequence is substituted by threonine; (4) the 214 or amino acid of the N-terminus that encompasses the signal sequence is substituted by glutamine; (5) the 253 or amino acid of the N-terminus that encompasses the signal sequence is substituted by threonine; (6) the 278 or amino acid of the N-terminus that encompasses the signal sequence is substituted by glycine; and (7) the 531 or amino acid of the N-terminus that encompasses the signal sequence is substituted by glycine; or wherein said amino acid substitution is one selected from the group consisting of (a) to (h) described below: (a) the 69 or amino acid of the N-terminal which encompasses the signal sequence is substituted by glycine; (b) the 203 or amino acid of the N-terminus that encompasses the signal sequence is substituted by threonine; (c) the 214 or amino acid of the N-terminus that encompasses the signal sequence is substituted by glutamine; (d) the 278 or amino acid of the N-terminus that encompasses the signal sequence is substituted by glycine; (e) the 531 or amino acid of the N-terminus that encompasses the signal sequence is substituted by glycine; (f) 154 o and 203 or amino acids of the N-terminal end encompassing the signal sequence are substituted by glycine and threonine, respectively; (g) the 214 or and the 253 or amino acids of the N-terminal which encompasses the signal sequence are substituted by glutamine and threonine, respectively; and (h) 69, 154 or 203 or amino acids of the N-terminus that encompasses the signal sequence are substituted by glycine, glycine and threonine, respectively.