Lipolytic enzymes LipA and LipB from Bacillus subtilis differ in regulation of gene expression, biochemical properties, and three-dimensional structure.
Bacillus subtilis secretes the lipolytic enzymes LipA and LipB. We show here that they are differentially expressed depending on the composition of the growth medium: LipA is produced in rich and in minimal medium, whereas LipB is present only in rich medium. A comparison of biochemical characteristics revealed that LipB is thermostable at pH 11 but becomes thermolabile at pH 5. However, construction of a variant carrying the substitution A76G in the conserved lipase pentapeptide reversed these effects. The atomic coordinates from the LipA crystal structure were used to build a three-dimensional structural model of LipB, which revealed that 43 out of 45 residues different from LipA are surface-located allowing to rationalize the differences observed in the substrate preferences of the two enzymes.
Eggert
T
T
Lehrstuhl Biologie der Mikroorganismen, Ruhr-Universität Bochum, Germany.
van Pouderoyen
G
G
Dijkstra
B W
BW
Jaeger
K E
KE
D001412:Bacillus subtilis / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D015153:Blotting, Western; D003470:Culture Media; D015971:Gene Expression Regulation, Enzymologic; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008049:Lipase / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity; D001616:beta-Galactosidase / Q000378:metabolism
D001426:Bacterial Proteins; D003470:Culture Media; C079999:LipA protein, Bacteria; C088618:lipase activator protein, Bacteria; D008049:Lipase; D001616:beta-Galactosidase