scholarly journals The organization of the purL gene encoding 5′-phosphoribosylformylglycinamide amidotransferase of Escherichia coli

1989 ◽  
Vol 264 (35) ◽  
pp. 21230-21238
Author(s):  
G Sampei ◽  
K Mizobuchi
1986 ◽  
Vol 261 (32) ◽  
pp. 14929-14935
Author(s):  
J W Chase ◽  
B A Rabin ◽  
J B Murphy ◽  
K L Stone ◽  
K R Williams

2000 ◽  
Vol 182 (17) ◽  
pp. 4862-4867 ◽  
Author(s):  
Marion Graupner ◽  
Huimin Xu ◽  
Robert H. White

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.


IUBMB Life ◽  
1997 ◽  
Vol 41 (5) ◽  
pp. 995-1003 ◽  
Author(s):  
Kiyohide Fushimi ◽  
Liqun Bai ◽  
Fumiaki Marumo ◽  
Sei Sasaki

1990 ◽  
Vol 68 (7-8) ◽  
pp. 1037-1044 ◽  
Author(s):  
Peter C. Loewen ◽  
Jacek Switala ◽  
Mark Smolenski ◽  
Barbara L. Triggs-Raine

Hydroperoxidase I (HPI) of Escherichia coli is a bifunctional enzyme exhibiting both catalase and peroxidase activities. Mutants lacking appreciable HPI have been generated using nitrosoguanidine and the gene encoding HPI, katG, has been cloned from three of these mutants using either classical probing methods or polymerase chain reaction amplification. The mutant genes were sequenced and the changes from wild-type sequence identified. Two mutants contained G to A changes in the coding strand, resulting in glycine to aspartate changes at residues 119 (katG15) and 314 (katG16) in the deduced amino acid sequence of the protein. A third mutant contained a C to T change resulting in a leucine to phenylalanine change at residue 139 (katG14). The Phe139-, Asp119-, and Asp314-containing mutants exhibited 13, < 1, and 18%, respectively, of the wild-type catalase specific activity and 43, 4, and 45% of the wild-type peroxidase specific activity. All mutant enzymes bound less protoheme IX than the wild-type enzyme. The sensitivities of the mutant enzymes to the inhibitors hydroxylamine, azide, and cyanide and the activators imidazole and Tris were similar to those of the wild-type enzyme. The mutant enzymes were more sensitive to high temperature and to β-mercaptoethanol than the wild-type enzyme. The pH profiles of the mutant catalases were unchanged from the wild-type enzyme.Key words: catalase, hydroperoxidase I, mutants, sequence analysis.


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