The DNA-binding domains of E. coli uracil-DNA glycosylase (Ung) and human replication protein A (hRPA) were studied using a general protocol developed in our laboratory for probing protein-DNA interactions. The procedure involves purification and mass spectrometric analysis of the nucleopeptide-products of a tryptically digested UV-crosslinked protein-nucleic acid complex. In the...
Three approaches toward the core of halichlorine and pinnaic acid are described. The first approach entails a racemic transannular nitrone-olefin [3+2] cycloaddition from nitrone 238. Construction of the nitrone 238 began with aldehyde 241. Another key feature in this route involved a ring-closing metathesis for the formation of a 14-membered...
The fragmentation characteristics of protonated peptides have been investigated using
tandem mass spectrometry (MS/MS) under various fragmentation regimes and detailed
density functional theory (DFT) reaction pathway calculations. The DFT calculations
predict novel salt-bridge stabilized transition structures as well as consecutive reactions
occurring in proton-bound dimers for some of the ions...