Carrier protein subjected to site-directed mutation and use thereof in preparation of vaccine

A conjugate of a site-directedly mutated group B meningococcal fHBP protein, wherein the conjugate is formed by coupling a site-directedly mutated protein with a modification compound, and the modification compound is a TLR2 receptor agonist;

• the site-directedly mutated protein is selected from:
• variants 2 and 3 in subfamily A or variant 1 in subfamily B of B meningococcal fHBP proteins, and the amino acid of at least one site on the protein is mutated into an unnatural amino acid;
• the mutation site is selected from:
• amino acids in the amino acid sequence of positions 2-10 in SEQ ID NO:
• 1, amino acids in the amino acid sequence of positions 2-10 in SEQ ID NO:
• 2, amino acids in the amino acid sequence of positions 2-10 in SEQ ID NO:
• 3;
• the amino acid at the mutation site of the site-directedly mutated protein is coupled with the modification compound to form the following structure:
• Wherein, AA is an amino acid before or after the mutation site,
• n=1-20, and R2 is a TLR2 receptor agonist.