Regulation of SulA cleavage by Lon protease by the C-terminal amino acid of SulA, histidine.
SulA protein, a cell division inhibitor in Escherichia coli, is degraded by Lon protease. The C-terminal eight residues of SulA have been shown to be recognized by Lon; however, it remains to be elucidated which amino acid in the C-terminus of SulA is critical for the recognition of SulA by Lon. To clarify this point, we constructed mutants of SulA with changes in the C-terminal residues, and examined the accumulation and stability of the resulting mutant SulA proteins in vivo. Substitution of the extreme C-terminal histidine residue with another amino acid led to marked accumulation and high stability of SulA in lon(+) cells. A SulA mutant in which the C-terminal eight residues were deleted (SulAC161) showed high accumulation and stability, but the addition of histidine to the C-terminus of SulAC161 (SulAC161+H) made it labile. Similarly, SulAC161+H fused to maltose-binding protein (MBP-SulAC161+H) formed a tight complex with and was degraded rapidly by Lon in vitro. Histidine competitively inhibited the degradation of MBP-SulA by Lon, while other amino acids did not. These results suggest that the histidine residue at the extreme C-terminus of SulA is recognized specifically by Lon, leading to a high-affinity interaction between SulA and Lon.
Ishii
Y
Y
Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
Amano
F
F
D018528:ATP-Binding Cassette Transporters; D049069:ATP-Dependent Proteases; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006639:Histidine / Q000502:physiology; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D009154:Mutation; D049070:Protease La; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012697:Serine Endopeptidases / Q000378:metabolism*
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D011993:Recombinant Fusion Proteins; C461599:maltose transport system, E coli; C053139:sulA protein, E coli; D006639:Histidine; D049069:ATP-Dependent Proteases; D012697:Serine Endopeptidases; C483567:Lon protein, E coli; D049070:Protease La; D000251:Adenosine Triphosphatases