Proteinase specificity of a proteinaceous inhibitor of subtilisin (SSI; Streptomyces subtilisin inhibitor) can be altered so as to strongly inhibit trypsin simply by replacing P1 methionine with lysine (with or without concomitant change of the P4 residue) through site-directed mutagenesis. Now the crystal structure of one such engineered SSI (P1 methionine converted to lysine and P4 methionine...

A number of elongation factor-2 kinase (eEF-2K) mutants were constructed to investigate features of this kinase that may be important in its activity. Typical protein kinases possess a highly conserved lysine residue in subdomain II which follows the GXGXXG motif of subdomain I. Mutation of two lysine residues, K340 and K346, which follow the GXGXXG motif in eEF-2K had no effect on activity, sh...

PYK (pyruvate kinase) plays a central role in the metabolism of many organisms and cell types, but the elucidation of the details of its function in a systems biology context has been hampered by the lack of specific high-affinity small-molecule inhibitors. High-throughput screening has been used to identify a family of saccharin derivatives which inhibit LmPYK (Leishmania mexicana PYK) activit...

The 14C labelled inactive protein obtained by sodium borohydride reduction of the enzyme, porphobilinogen synthase of Rhodopseudomonas spheroides, in the presence of [4-14C]5-aminolevulinic acid, gave on acid hydrolysis and subsequent electrophoresis or two-dimensional chromatography a major radioactive spot which was confirmed to be N-epsilon-[4-(-5aminovaleric acid)]lysine (ALA-lysine) by com...

The emerging view of Nε-lysine acetylation in eukaryotes is of a relatively abundant post-translational modification (PTM) that has a major impact on the function, structure, stability and/or location of thousands of proteins involved in diverse cellular processes. This PTM is typically considered to arise by the donation of the acetyl group from acetyl-coenzyme A (acCoA) to the ε-amino group o...

Earlier studies have indicated the marked resistance of two pronase endopeptidases to denaturation in high concentrations of urea or guanidine hydrochloride (Siegel, S., and Awad, W. M., Jr. (1973) d BioL Chem 248, 3233-3240). One component has only a single residue of lysine and the other has none. The consideration arose that lysine-containing peptide segments may be less stable than those co...

Heteronuclear NMR spectroscopy and other experiments indicate that the true substrate of the E l component of 2-0x0 acid dehydrogenase complexes is not lipoic acid but the lipoyl domain of the E2 component. E l can recognize the lipoyllysine residue as such, but reductive acylation ensues only if the domain to which the lipoyl group is attached is additionally recognized by virtue of a mosaic o...

SET domain lysine methyltransferases are known to catalyze site and state-specific methylation of lysine residues in histones that is fundamental in epigenetic regulation of gene activation and silencing in eukaryotic organisms. Here we report the three-dimensional solution structure of the SET domain histone lysine methyltransferase (vSET) from Paramecium bursaria chlorella virus 1 bound to co...

Dot1 is a non-SET domain protein that methylates histone H3 at lysine 79, a surface-exposed residue that lies within the globular domain. In the context of a nucleosome, H3 lysine 79 is located in close proximity with lysine 123 of histone H2B, a major site for ubiquitination by Rad6. Here we show that Rad6-mediated ubiquitination of H2B lysine 123 is important for efficient methylation of lysi...

The rotors of ATP synthases turn about 100 times every second. One essential component of the rotor is a ring of hydrophobic c-subunits in the membrane domain of the enzyme. The rotation of these c-rings is driven by a transmembrane proton-motive force, and they turn against a surface provided by another membrane protein, known as subunit a. Together, the rotating c-ring and the static subunit ...