A reductionist approach: Defining the scope of selective glycation, a native non-enzymatic posttranslational modification
Abstract: In the present work, a one-bead-one-compound (oboc) arginine-containing peptide library was interrogated to address the unmet need to unravel the microenvironment effect of reactive arginine sites towards MG, the most potent and prevalent glycating agent in vivo. We implemented three distinct colorimetric detection schemes to screen the i-2, i-1, i+2 and i+1 positions flanking arginine ... read morein the i-position. One assay provided a readout for the overall modification whereas the latter two assays were based on commercial antibodies specific for the AGEs, argypyrimidine (ArgPy) or hydroimidazolone (MG-H). Of note, three consensus sequences emerged. The first assay showed a preference for histidine and glycine in the i-1 and i+1 positions, respectively. For the anti-MG-H, there was a strong preference for tyrosine at the i+1 and i+2 positions. A possible synergy between glutamate and serine in the i-1 and i-2 also emerged. For anti-ArgPy assay, aromatic residues were enriched in all position with a preference for tyrosine. Unexpectedly, a sequence motif also emerged for the non-hits with two or more acidic amino acid residues, glutamates and/or aspartates. Altogether, these studies were the first to generate strong sequence motif, both for enhancing and suppressing conversion to AGEs Furthermore, these studies have led to the development of a platform that may be useful for either screening alternative aldehydes or exploring N-terminal amino acid sequences that lead to excellent conversion to AGEs.
Thesis (Ph.D.)--Tufts University, 2018.
Submitted to the Dept. of Chemistry.
Advisor: Rebecca Scheck.
Committee: Krishna Kumar, and Clay Bennett.
Keywords: Cellular biology, Biochemistry, and Biology.read less