Reaction mechanism of Escherichia coli cystathionine .gamma.-synthase: direct evidence for a pyridoxamine derivative of vinylgloxylate as a key intermediate in pyridoxal phosphate dependent .gamma.-elimination and .gamma.-replacement reactions

Biochemistry ◽  
1990 ◽  
Vol 29 (2) ◽  
pp. 442-451 ◽  
Author(s):  
Peter Brzovic ◽  
Elizabeth Litzenberger Holbrook ◽  
Ronald C. Greene ◽  
Michael F. Dunn
Keyword(s):  
Escherichia Coli ◽  
Reaction Mechanism ◽  
Pyridoxal Phosphate ◽  
Direct Evidence

scholarly journals Structure and Reaction Mechanism of YcjR, an Epimerase That Facilitates the Interconversion of d-Gulosides to d-Glucosides in Escherichia coli

Biochemistry ◽  
2020 ◽  
Vol 59 (22) ◽  
pp. 2069-2077
Author(s):  
Mark F. Mabanglo ◽  
Jamison P. Huddleston ◽  
Keya Mukherjee ◽  
Zane W. Taylor ◽  
Frank M. Raushel
Keyword(s):  
Escherichia Coli ◽  
Reaction Mechanism

scholarly journals High-Level Conversion of l-lysine into Cadaverine by Escherichia coli Whole Cell Biocatalyst Expressing Hafnia alvei l-lysine Decarboxylase

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1184 ◽  
Author(s):  
Kim ◽  
Baritugo ◽  
Oh ◽  
Kang ◽  
Jung ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Protein Expression ◽  
Pyridoxal Phosphate ◽  
Lysine Decarboxylase ◽  
Hafnia Alvei ◽  
Whole Cell ◽  
E Coli ◽  
Whole Cell Biocatalyst ◽  
High Level ◽  
Whole Cell Bioconversion

Cadaverine is a C5 diamine monomer used for the production of bio-based polyamide 510. Cadaverine is produced by the decarboxylation of l-lysine using a lysine decarboxylase (LDC). In this study, we developed recombinant Escherichia coli strains for the expression of LDC from Hafnia alvei. The resulting recombinant XBHaLDC strain was used as a whole cell biocatalyst for the high-level bioconversion of l-lysine into cadaverine without the supplementation of isopropyl β-d-1-thiogalactopyranoside (IPTG) for the induction of protein expression and pyridoxal phosphate (PLP), a key cofactor for an LDC reaction. The comparison of results from enzyme characterization of E. coli and H. alvei LDC revealed that H. alvei LDC exhibited greater bioconversion ability than E. coli LDC due to higher levels of protein expression in all cellular fractions and a higher specific activity at 37 °C (1825 U/mg protein > 1003 U/mg protein). The recombinant XBHaLDC and XBEcLDC strains were constructed for the high-level production of cadaverine. Recombinant XBHaLDC produced a 1.3-fold higher titer of cadaverine (6.1 g/L) than the XBEcLDC strain (4.8 g/L) from 10 g/L of l-lysine. Furthermore, XBHaLDC, concentrated to an optical density (OD600) of 50, efficiently produced 136 g/L of cadaverine from 200 g/L of l-lysine (97% molar yield) via an IPTG- and PLP-free whole cell bioconversion reaction. Cadaverine synthesized via a whole cell biocatalyst reaction using XBHaLDC was purified to polymer grade, and purified cadaverine was successfully used for the synthesis of polyamide 510. In conclusion, an IPTG- and PLP-free whole cell bioconversion process of l-lysine into cadaverine, using recombinant XBHaLDC, was successfully utilized for the production of bio-based polyamide 510, which has physical and thermal properties similar to polyamide 510 synthesized from chemical-grade cadaverine.

scholarly journals The Geobacillus stearothermophilus V iscS Gene, Encoding Cysteine Desulfurase, Confers Resistance to Potassium Tellurite in Escherichia coli K-12

2003 ◽  
Vol 185 (19) ◽  
pp. 5831-5837 ◽  
Author(s):  
Juan C. Tantaleán ◽  
Manuel A. Araya ◽  
Claudia P. Saavedra ◽  
Derie E. Fuentes ◽  
José M. Pérez ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pyridoxal Phosphate ◽  
Geobacillus Stearothermophilus ◽  
Cysteine Desulfurase ◽  
Tellurite Resistance ◽  
Potassium Tellurite ◽  
E Coli ◽  
Directed Mutation ◽  
Auxotrophic Requirement ◽  
K 12

ABSTRACT Many eubacteria are resistant to the toxic oxidizing agent potassium tellurite, and tellurite resistance involves diverse biochemical mechanisms. Expression of the iscS gene from Geobacillus stearothermophilus V, which is naturally resistant to tellurite, confers tellurite resistance in Escherichia coli K-12, which is naturally sensitive to tellurite. The G. stearothermophilus iscS gene encodes a cysteine desulfurase. A site-directed mutation in iscS that prevents binding of its pyridoxal phosphate cofactor abolishes both enzyme activity and its ability to confer tellurite resistance in E. coli. Expression of the G. stearothermophilus iscS gene confers tellurite resistance in tellurite-hypersensitive E. coli iscS and sodA sodB mutants (deficient in superoxide dismutase) and complements the auxotrophic requirement of an E. coli iscS mutant for thiamine but not for nicotinic acid. These and other results support the hypothesis that the reduction of tellurite generates superoxide anions and that the primary targets of superoxide damage in E. coli are enzymes with iron-sulfur clusters.

Ortho ester hydrolysis: direct evidence for a three-stage reaction mechanism

1979 ◽  
Vol 101 (10) ◽  
pp. 2669-2677 ◽  
Author(s):  
M. Ahmad ◽  
R. G. Bergstrom ◽  
M. J. Cashen ◽  
Y. Chiang ◽  
A. J. Kresge ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Direct Evidence ◽  
Ester Hydrolysis ◽  
Ortho Ester
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