It is now widely appreciated that we are entering into a post-antibiotic era. Resistance of killer microbes has reached crisis levels, and it is now possible to die from an infected splinter. The everninomicins are a class of natural product antibiotics that have been shown to be effective at killing multiple drug resistant bacterial infections in humans. The biological target of these drugs is unique from known classes of antibiotics and for this reason it is expected that evolution of resistance to these compounds will be slower than to derivatives of existing classes of drugs (e.g. a derivative penicillin). Everninomicin A, also called Ziracin, was advanced into clinical trials and proceeded successfully into late stage III trials. Tragically, Ziracin failed at the end of Phase III where it was discovered that this compound had borderline toxicity in sick patients. Ziracin is a complex and large molecule by antibiotic standards, and this toxicity is likely due to a substructure in this giant molecule. We hypothesize that if the disadvantageous substructure could be changed, we could eliminate the borderline toxicity of this compound and correct its trajectory toward the clinic, where it is so desperately needed. Due to its high promise as an antibiotic, Ziracin has actually been chemically synthesized and it required 140 chemical steps to generate Ziracin. Hence, it is impractical to use chemical synthesis to generate Ziracin analogs to overcome the toxicity of this compound. We have undertaken an ambitious program to change the structure of Ziracin-like compounds using synthetic biology. We have identified the genetic blueprints for Ziracin biosynthesis, and are using unique gene-replacement technologies, developed in the LBS specifically for this organism, to study the biosynthesis of this exiting antibiotic lead compound and to modify its structure.