Abstract: Biosensors including a nucleic acid encoding a PcaU protein, a PobR protein, a CatM protein, a PcaR protein, or a TphR protein are provided. In some examples, the biosensors include a promoter regulated by the sensed molecule operably linked to a reporter gene. The biosensors may be included in a vector or in cells including one or more of the biosensors or vectors. Modified chorismate pyruvate lyase (UbiC) and modified paraoxonase (PON1) proteins including one or more amino acid substitutions are provided. Finally, methods of selecting biocatalysts with increased activity including transforming a library of cells expressing a biosensor with one or more nucleic acids encoding one or more mutations in a gene involved in a biosynthesis pathway, determining activity of the reporter protein; and selecting a cell with increased reporter protein activity as expressing a biocatalyst with increased activity are provided.

Abstract: The present disclosure provides improved methods for controlled cyclization of peptoid dimers to form N,N?-2,5-diketopiperazines (N,N?-2,5-DKPs) with significant selectivity. In at least some examples, selectivity is based on a serendipitous conglomeration of slow exchange of amide rotamers, steric repulsion from the degree of ?-substitution, and the geometric bulk of an amine nucleophile. By varying reaction conditions, the selectivity of the reaction and formation of a particular N,N?-2,5-DKP can be switched. The cyclization works in the presence of a variety of protection groups and diverse functionalities. The teachings herein provide techniques for synthesizing N,N?-2,5-DKPs that can be readily docked with drug candidates for shuttling across the blood brain barrier. This method provides a facile way to produce substituted DKPs containing groups ready for post-modification to include docking drug candidates.

Abstract: The present disclosure provides improved methods for controlled cyclization of peptoid dimers to form N,N?-2,5-diketopiperazines (N,N?-2,5-DKPs) with significant selectivity. In at least some examples, selectivity is based on a serendipitous conglomeration of slow exchange of amide rotamers, steric repulsion from the degree of ?-substitution, and the geometric bulk of an amine nucleophile. By varying reaction conditions, the selectivity of the reaction and formation of a particular N,N?-2,5-DKP can be switched. The cyclization works in the presence of a variety of protection groups and diverse functionalities. The teachings herein provide techniques for synthesizing N,N?-2,5-DKPs that can be readily docked with drug candidates for shuttling across the blood brain barrier. This method provides a facile way to produce substituted DKPs containing groups ready for post-modification to include docking drug candidates.

Abstract: Disclosed herein are methods of identifying polymers having particular biological or physical characteristics from in vivo generated libraries of polymers. Methods of generating in vivo polymer libraries are also described. Polymers identified using the methods of the invention are also described.

Abstract: Apparatus and method for heterodyne-generated, two-dimensional detector array using a single detector. Synthetic-array heterodyne detection, permits a single-element optical detector to behave as though it were divided into an array of separate heterodyne detector elements. A fifteen-element synthetic array has successfully been experimentally realized on a single-element detector, permitting all of the array elements to be read out continuously and in parallel from one electrical connection. A CO.sub.2 laser and a single-element HgCdTe photodiode are employed. A different heterodyne local oscillator frequency is incident upon the spatially resolvable regions of the detector surface. Thus, different regions are mapped to different heterodyne beat frequencies. One can determine where the photons were incident on the detector surface even though a single electrical connection to the detector is used.