J. Biol. Chem., Vol. 259, Issue 14, 8713-8717, 07, 1984
Inactivation and proteolysis of heat-sensitive adenylate kinase of Escherichia coli CR341 T28
N Guiso, S Michelson and O Barzu
Adenylate kinase from Escherichia coli K12 (strains CR341 and CR341 T28, a
temperature-sensitive mutant) was purified by a two-step chromatographic
procedure. Denaturation by heat above 60 degrees C of pure or crude
preparations of adenylate kinase from both strains of bacteria was shown to
be "reversible" if the enzyme was converted to the random coiled state by
guanidinium chloride after heat treatment. Like other small monomeric
proteins, adenylate kinase refolded rapidly to the native active state by
dilution of guanidinium chloride. Adenylate kinase from the mutant strain
was irreversibly inactivated by exposure of crude extracts at 40 degrees C.
This inactivation is due to proteolysis which follows thermal denaturation
(or transconformation) of mutant adenylate kinase at 40 degrees C. ATP, P1,
P5-di(adenosine 5')-pentaphosphate, and anti-adenylate kinase antibodies
protected the thermosensitive adenylate kinase in crude extracts against
denaturation and proteolysis at 40 degrees C.