Disease relevance of ECs0173

• Structure of Escherichia coli UMP kinase differs from that of other nucleoside monophosphate kinases and sheds new light on enzyme regulation [1].
• UMP kinase from the Gram-positive bacterium Bacillus subtilis is strongly dependent on GTP for optimal activity [2].
• Despite sequence identity of only 18% over 203 amino acids, alignment of UMP kinase from E. coli with carbamate kinase from Enterococcus faecalis by hydrophobic cluster analysis and threading suggested the conservation of the overall structure, except for a small subdomain (absent in UMP kinase) [3].

High impact information on ECs0173

• These results indicate that besides its catalytic function in the de novo pyrimidine biosynthesis, E. coli UMP-kinase fulfils an additional, but previously unrecognized role in the regulation of the carAB operon [4].
• The specific localization of UMP kinase might also be related to its putative role in cell division [5].
• Mono- and polyclonal antibodies directed against UMP kinase from Escherichia coli were tested with the intact protein or with fragments obtained by deletion mutagenesis [5].
• These data indicate that the UTP and GTP binding sites in UMP kinase are only partially overlapping [5].
• Immunogold labeling of UMP kinase in whole E. coli cells shows a localization of the protein near the bacterial membranes [5].

Biological context of ECs0173

• Although overexpression of pyrH41 results in UMP-kinase levels far above that of a wild-type strain, pyrimidine-specific repression of the carAB operon is not restored under these conditions [4].
• UMP phosphorylation, a key step for pyrimidine nucleotide biosynthesis, is catalyzed in bacteria by UMP kinase (UMPK), an enzyme specific for UMP that is dissimilar to the eukaryotic UMP/CMP kinase or to other nucleoside monophosphate kinases [6].

Analytical, diagnostic and therapeutic context of ECs0173

• A variant of UMP-kinase, obtained by site-directed mutagenesis (Asp159Asn), which is similar to the wild-type enzyme in its stability and kinetic properties, has a much increased water solubility (> 5 mg protein/mL) even at neutral pH [7].
• As detected in enzyme-linked immunosorbent assay tests, the carboxy-terminal quarter of UMP kinase is immunodominant [5].
• Antibodies raised against recombinant B. subtilis UMP kinase recognized the protein both in soluble extract and in immunoelectron microscopy [8].
• First-time crystallization and preliminary X-ray crystallographic analysis of a bacterial-archaeal type UMP kinase, a key enzyme in microbial pyrimidine biosynthesis [6].

References