Chemical Perspectives on Protein Glycation

Chapter 1:An introduction to protein glycation. Here, a review of the reaction of proteins and sugars to form advanced glycation endproducts (AGEs) is given, as well as an identification of the more common AGE structures, with emphasis on those derived from methylglyoxal (MGO). Finally, the application of chemical synthesis to the study of AGEs is discussed.;Chapter 2: The methylglyoxal hydroimidazolones (MG-Hs) are the most common argininederived AGE. We report routes for MG-H-amino acid building blocks suitably protected for solid phase peptide synthesis (SPPS). Incorporation of MG-Hs into peptides allowed for investigations into their biochemical properties. We discovered that the MG-H3 isomer exhibits redox activity, oxidizing to the imidazolone MG-13. Notably, this product was found to readily hydrolyze to regenerate arginine and produce pyruvate, a useful cellular metabolite.;Chapter 3: Although anti-AGE antibodies have been widely used in the study of AGE biology, these reagents are often produced using poorly characterized immunogens. We applied our MG-H syntheses to developing chemically homogenous peptides for immunization. With these materials, we were able to produce antibodies that recognized each of the three regioisomers with varying levels of specificity. The anti-(MG-H) antibodies generated could be applied to detection of intracellular MG-Hs using immunofluorescence spectroscopy. Interestingly, we found that formation of MG-Hs upon treatment with MGO is most concentrated in the nucleus.;Chapter 4: We report the computationally-driven design and synthesis of the first fluorogenic sensor for MGO. This fluorophore is selective for MGO over other dicarbonyls tested and is suitable for detecting MGO in complex systems, including serum and within living cells. We also report the utility of this compound in estimating plasma concentrations of MGO.;Chapter 5: This chapter deviates from the theme of chapters 1-4 and reports the development of a new platform for combinatorial chemistry that uses RFID encoding to track compound identity. Synthesis and screening of library members is performed on ultra-small microtransponders (p-Chips), whose fluorescence and RFID are simultaneously determined using the Simuplex, a flow cytometer-like instrument. By redesigning the p-Chip surface and identifying strategies for their chemical functionalization, we were able to synthesize and screen a split-pool peptide library for antibody binding and rapidly identify a consensus sequence for epitope recognition.