Understanding Enzyme Mechanism through Protein Chimeragenesis.- Chemical Protein Engineering: Synthetic and Semisynthetic Peptides and Proteins.- Native Chemical Ligation: SemiSynthesis of Post-translationally Modified Proteins and Biological Probes.- Chemical Methods for Mimicking Post-Translational Modifications.- Noncanonical Amino Acids in Protein Science and Engineering.- Fidelity Mechanisms of the Aminoacyl-tRNA Synthetases.- Specialized Components of the Translational Machinery for Unnatural Amino Acid Mutagenesis: tRNAs, Aminoacyl-tRNA Synthetases, and Ribosomes.- In Vivo Studies of Receptors and Ion Channels with Unnatural Amino Acids.- Synthesis of Modified Proteins Using Misacylated tRNAs.- Cell-Free Synthesis of Proteins with Unnatural Amino Acids. The PURE System and Expansion of the Genetic Code.- Engineering Nucleobases and Polymerases for an Expanded Genetic Alphabet.- Understanding Membrane Proteins. How to Design Inhibitors of Transmembrane Protein-Protein Interactions.