In the first experimental use of algorithms that employ structure-based molecular modeling to optimize deimmunized drug candidates, researchers complement their prior sequence-based deimmunizing algorithms and expand the tool kit of protein engineering technologies to use in next generation drug development. The P99 beta lactamase peptide backbone is shown in complex with a beta lactam substrate , which is rendered as a stick figure with carbon in cyan, nitrogen in dark blue, oxygen in red, and sulfur in yellow.