The hyp operon gene products are required for the maturation of catalytically active hydrogenase isoenzymes in Escherichia coli

1992 ◽  
Vol 158 (6) ◽  
Author(s):  
A. Jacobi ◽  
R. Rossmann ◽  
A. B�ck
Keyword(s):  
Escherichia Coli ◽  
Gene Products ◽  
Catalytically Active ◽  
Operon Gene

scholarly journals Physical and genetic characterization of the melibiose operon and identification of the gene products in Escherichia coli.

1984 ◽  
Vol 259 (3) ◽  
pp. 1807-1812 ◽  
Author(s):  
M Hanatani ◽  
H Yazyu ◽  
S Shiota-Niiya ◽  
Y Moriyama ◽  
H Kanazawa ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genetic Characterization ◽  
Gene Products

scholarly journals Identification of the Gene Encoding Sulfopyruvate Decarboxylase, an Enzyme Involved in Biosynthesis of Coenzyme M

2000 ◽  
Vol 182 (17) ◽  
pp. 4862-4867 ◽  
Author(s):  
Marion Graupner ◽  
Huimin Xu ◽  
Robert H. White
Keyword(s):  
Escherichia Coli ◽  
Second Step ◽  
Gene Products ◽  
Methanococcus Jannaschii ◽  
Coenzyme M ◽  
Gene Encoding ◽  
Fourth Step

ABSTRACT The products of two adjacent genes in the chromosome ofMethanococcus jannaschii are similar to the amino and carboxyl halves of phosphonopyruvate decarboxylase, the enzyme that catalyzes the second step of fosfomycin biosynthesis inStreptomyces wedmorensis. These two M. jannaschii genes were recombinantly expressed inEscherichia coli, and their gene products were tested for the ability to catalyze the decarboxylation of a series of α-ketoacids. Both subunits are required to form an α6β6 dodecamer that specifically catalyzes the decarboxylation of sulfopyruvic acid to sulfoacetaldehyde. This transformation is the fourth step in the biosynthesis of coenzyme M, a crucial cofactor in methanogenesis and aliphatic alkene metabolism. The M. jannaschiisulfopyruvate decarboxylase was found to be inactivated by oxygen and reactivated by reduction with dithionite. The two subunits, designated ComD and ComE, comprise the first enzyme for the biosynthesis of coenzyme M to be described.

Evidence for two recA genes mediating DNA repair in Bacillus megaterium

Microbiology ◽  
2005 ◽  
Vol 151 (3) ◽  
pp. 775-787 ◽  
Author(s):  
Hannes Nahrstedt ◽  
Christine Schröder ◽  
Friedhelm Meinhardt
Keyword(s):  
Escherichia Coli ◽  
Dna Repair ◽  
Mitomycin C ◽  
Bacillus Megaterium ◽  
Functional Complementation ◽  
Homologous Gene ◽  
Gene Products ◽  
Null Mutant ◽  
Promoter Regions ◽  
Increased Sensitivity

Isolation and subsequent knockout of a recA-homologous gene in Bacillus megaterium DSM 319 resulted in a mutant displaying increased sensitivity to mitomycin C. However, this mutant did not exhibit UV hypersensitivity, a finding which eventually led to identification of a second functional recA gene. Evidence for recA duplicates was also obtained for two other B. megaterium strains. In agreement with potential DinR boxes located within their promoter regions, expression of both genes (recA1 and recA2) was found to be damage-inducible. Transcription from the recA2 promoter was significantly higher than that of recA1. Since a recA2 knockout could not be achieved, functional complementation studies were performed in Escherichia coli. Heterologous expression in a RecA null mutant resulted in increased survival after UV irradiation and mitomycin C treatment, proving both recA gene products to be functional in DNA repair. Thus, there is evidence for an SOS-like pathway in B. megaterium that differs from that of Bacillus subtilis.

scholarly journals Expression of catalytically active rat S -adenosylmethionine decarboxylase in Escherichia coli

FEBS Letters ◽  
1989 ◽  
Vol 258 (1) ◽  
pp. 123-126 ◽  
Author(s):  
Paula Salmikangas ◽  
Marja-Riitta Keranen ◽  
Antti Pajunen
Keyword(s):  
Escherichia Coli ◽  
Adenosylmethionine Decarboxylase ◽  
Catalytically Active

scholarly journals Thermal inactivation and chaperonin-mediated renaturation of mitochondrial aspartate aminotransferase

1998 ◽  
Vol 334 (1) ◽  
pp. 219-224 ◽  
Author(s):  
James M. LAWTON ◽  
Shawn DOONAN
Keyword(s):  
Escherichia Coli ◽  
Aspartate Aminotransferase ◽  
Thermal Inactivation ◽  
Active Form ◽  
Active Conformation ◽  
E Coli ◽  
Catalytically Active ◽  
Mitochondrial Aspartate Aminotransferase ◽  
Chaperonin 10 ◽  
Chaperonin 60

Mitochondrial aspartate aminotransferase is inactivated irreversibly on heating. The inactivated protein aggregates, but aggregation is prevented by the presence of the chaperonin 60 from Escherichia coli (GroEL). The chaperonin increases the rate of thermal inactivation in the temperature range 55–65 °C but not at lower temperatures. It has previously been shown [Twomey and Doonan (1997) Biochim. Biophys. Acta 1342, 37–44] that the enzyme switches to a modified, but catalytically active, conformation at approx. 55–60 °C and the present results show that this conformation is recognized by and binds to GroEL. The thermally inactivated protein can be released from GroEL in an active form by the addition of chaperonin 10 from E. coli (GroES)/ATP, showing that inactivation is not the result of irreversible chemical changes. These results suggest that the irreversibility of thermal inactivation is due to the formation of an altered conformation with a high kinetic barrier to refolding rather than to any covalent changes. In the absence of chaperonin the unfolded molecules aggregate but this is a consequence, rather than the cause, of irreversible inactivation.

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