Chuan-Fa Liu

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Lysine acetylation and its regulatory enzymes are known to have pivotal roles in mammalian cellular physiology. However, the extent and function of this modification in prokaryotic cells remain largely unexplored, thereby presenting a hurdle to further functional study of this modification in prokaryotic systems. Here we report the first global screening of(More)
Previous experiments suggest a connection between the N-alpha-acetylation of proteins and sensitivity of cells to apoptotic signals. Here, we describe a biochemical assay to detect the acetylation status of proteins and demonstrate that protein N-alpha-acetylation is regulated by the availability of acetyl-CoA. Because the antiapoptotic protein Bcl-xL is(More)
Understanding the molecular mechanisms behind regulation of chromatin folding through covalent modifications of the histone N-terminal tails is hampered by a lack of accessible chromatin containing precisely modified histones. We study the internal folding and intermolecular self-association of a chromatin system consisting of saturated 12-mer nucleosome(More)
Nucleosome-nucleosome interaction plays a fundamental role in chromatin folding and self-association. The cation-induced condensation of nucleosome core particles (NCPs) displays properties similar to those of chromatin fibers, with important contributions from the N-terminal histone tails. We study the self-association induced by addition of cations(More)
The HIV-1 protein Vpr is critical for a number of viral functions including a unique ability to arrest T-cells at a G2/M checkpoint and induce subsequent apoptosis. It has been shown to interact specifically with the second UBA (ubiquitin associated) domain found in the DNA repair protein HHR23A, a highly evolutionarily conserved protein. This domain is a(More)
With two β-mercaptoethyl groups on the N, a tertiary amide of structure 1 is always poised for intramolecular thioesterification however it flips about the C-N bond. It is shown that a peptide with such a C-terminal N,N-bis(2-mercaptoethyl)-amide (BMEA) can be used directly for native chemical ligation (NCL). These BMEA peptides are easily prepared with(More)
A robust chemical ubiquitination method was developed. The method employed a genetically incorporated azidonorleucine as an orthogonal lysine precursor for the installation of a Gly residue bearing an Nα-auxiliary which mediated the ligation between ubiquitin(1-75)-thioester and the target protein. To demonstrate our methodology, a model protein, K48-linked(More)
A thiol group introduced on the gamma-carbon of lysine mediates robust native chemical ligation at both the alpha- and epsilon-amines in two consecutive steps. Desulfurization then affords the final product, in which the lysine residue at the ligation site has an isopeptide bond on its side chain. The method is useful for the synthesis of proteins(More)