Antibiotic resistance within MRSA is due to the versatility, flexibility and abundance of the salt bridge interactions that transmit a series of conformational changes from the allosteric site to the active site of PBP2a. This signal culminates in a shift of the beta3-beta4 loop which now allows substrates such as peptidoglycan or various antibiotics into the active site. The exact pathway of this salt bridge cascade is dependent on the size and structure of the allosteric modulator which alters both the identity and number of residues involved. Ultimately this creates a salt bridge cascade unique to each modulator rather than having one set pathway. Mutations at any point along these different pathways that result in the loss or diversion of the allosteric signal away from the active site results in an antibiotic resistant phenotype. As a result, a loss of charge adaption along the pathway conferred by an allosterically bound antibiotic will prevent a signal from reaching the active site. However, this same mutation will not affect the signal pathway created by an allosterically bound peptidoglycan due to the uniqueness of each pathway which allows for the survival of the MRSA strain.