FIG. 1.

Schematic representation of UMP kinase and of its fragments generated by deletion mutagenesis and SDS-PAGE analysis of peptides overproduced in E. coli. (A) Key residues involved in substrate binding, catalysis, or regulation by nucleotides are indicated by vertical bars. (B) Total bacterial extract after sonication (50 μg of protein). (C) Pellet equivalent to 50 μg of total extract after centrifugation for 5 min at 10,000 × g. The molecular mass markers are from New England Biolabs.