In vivo photoinactivation of Escherichia coli ribonucleotide reductase by near-ultraviolet light

Nature ◽  
1977 ◽  
Vol 267 (5611) ◽  
pp. 546-548 ◽  
Author(s):  
JULIUS PETERS
Keyword(s):  
Escherichia Coli ◽  
Ultraviolet Light ◽  
Ribonucleotide Reductase ◽  
Near Ultraviolet

Nerve autofluorescence in near-ultraviolet light markedly enhances nerve visualization in vivo

2021 ◽  
Author(s):  
Fernando Dip ◽  
Pedro Bregoli ◽  
Jorge Falco ◽  
Kevin P. White ◽  
Raúl J. Rosenthal
Keyword(s):  
Ultraviolet Light ◽  
Near Ultraviolet

NEAR-ULTRAVIOLET MODIFICATION OF ESCHERICHIA COLI B UBIQUINONE IN VIVO AND IN VITRO

1974 ◽  
Vol 19 (5) ◽  
pp. 321-328 ◽  
Author(s):  
Harold Werbin ◽  
Bala D. Lakchaura ◽  
John Jagger
Keyword(s):  
Escherichia Coli ◽  
Near Ultraviolet ◽  
Escherichia Coli B

scholarly journals Induction of size reduction in Escherichia coli by near-ultraviolet light

1985 ◽  
Vol 146 (3) ◽  
pp. 605-610 ◽  
Author(s):  
Adriano CALDEIRA de ARAUJO ◽  
Alain FAVRE
Keyword(s):  
Escherichia Coli ◽  
Ultraviolet Light ◽  
Size Reduction ◽  
Near Ultraviolet

Near ultraviolet light inactivation of dihydroxyacid dehydratase in Escherichia coli

1993 ◽  
Vol 14 (6) ◽  
pp. 609-613 ◽  
Author(s):  
E. Smyk-Randall ◽  
O.R. Brown ◽  
A. Wilke ◽  
A. Eisenstark ◽  
D.H. Flint
Keyword(s):  
Escherichia Coli ◽  
Ultraviolet Light ◽  
Near Ultraviolet

scholarly journals In Vivo Assay for Low-Activity Mutant Forms of Escherichia coli Ribonucleotide Reductase

2003 ◽  
Vol 185 (4) ◽  
pp. 1167-1173 ◽  
Author(s):  
Monica Ekberg ◽  
Pernilla Birgander ◽  
Britt-Marie Sjöberg
Keyword(s):  
Escherichia Coli ◽  
Ribonucleotide Reductase ◽  
Active Site ◽  
Site Directed Mutagenesis ◽  
In Vitro Assays ◽  
Tyrosyl Radical ◽  
In Vivo Assay ◽  
Radical Transfer

ABSTRACT Ribonucleotide reductase (RNR) catalyzes the essential production of deoxyribonucleotides in all living cells. In this study we have established a sensitive in vivo assay to study the activity of RNR in aerobic Escherichia coli cells. The method is based on the complementation of a chromosomally encoded nonfunctional RNR with plasmid-encoded RNR. This assay can be used to determine in vivo activity of RNR mutants with activities beyond the detection limits of traditional in vitro assays. E. coli RNR is composed of two homodimeric proteins, R1 and R2. The R2 protein contains a stable tyrosyl radical essential for the catalysis that takes place at the R1 active site. The three-dimensional structures of both proteins, phylogenetic studies, and site-directed mutagenesis experiments show that the radical is transferred from the R2 protein to the active site in the R1 protein via a radical transfer pathway composed of at least nine conserved amino acid residues. Using the new assay we determined the in vivo activity of mutants affecting the radical transfer pathway in RNR and identified some residual radical transfer activity in two mutant R2 constructs (D237N and W48Y) that had previously been classified as negative for enzyme activity. In addition, we show that the R2 mutant Y356W is completely inactive, in sharp contrast to what has previously been observed for the corresponding mutation in the mouse R2 enzyme.

scholarly journals Inactivation of membrane transport in Escherichia coli by near-ultraviolet light.

1976 ◽  
Vol 126 (1) ◽  
pp. 140-146 ◽  
Author(s):  
A L Koch ◽  
R J Doyle ◽  
H E Kubitschek
Keyword(s):  
Escherichia Coli ◽  
Membrane Transport ◽  
Ultraviolet Light ◽  
Near Ultraviolet

scholarly journals Replication Rapidly Recovers and Continues in the Presence of Hydroxyurea inEscherichia coli

2017 ◽  
Vol 200 (6) ◽  
Author(s):  
Samvel A. Nazaretyan ◽  
Neda Savic ◽  
Michael Sadek ◽  
Brandy J. Hackert ◽  
Justin Courcelle ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Dna Replication ◽  
Ribonucleotide Reductase ◽  
Specific Inhibitor ◽  
Content Type ◽  
Ribonucleotide Reductases ◽  
The Stability ◽  
Deoxyribonucleoside Triphosphate

ABSTRACTIn both prokaryotes and eukaryotes, hydroxyurea is suggested to inhibit DNA replication by inactivating ribonucleotide reductase and depleting deoxyribonucleoside triphosphate pools. In this study, we show that the inhibition of replication inEscherichia coliis transient even at concentrations of 0.1 M hydroxyurea and that replication rapidly recovers and continues in its presence. The recovery of replication does not require the alternative ribonucleotide reductases NrdEF and NrdDG or the translesion DNA polymerases II (Pol II), Pol IV, and Pol V. Ribonucleotides are incorporated at higher frequencies during replication in the presence of hydroxyurea. However, they do not contribute significantly to the observed synthesis or toxicity. Hydroxyurea toxicity was observed only under conditions where the stability of hydroxyurea was compromised and by-products known to damage DNA directly were allowed to accumulate. The results demonstrate that hydroxyurea is not a direct or specific inhibitor of DNA synthesisin vivoand that the transient inhibition observed is most likely due to a general depletion of iron cofactors from enzymes when 0.1 M hydroxyurea is initially applied. Finally, the results support previous studies suggesting that hydroxyurea toxicity is mediated primarily through direct DNA damage induced by the breakdown products of hydroxyurea, rather than by inhibition of replication or depletion of deoxyribonucleotide levels in the cell.IMPORTANCEHydroxyurea is commonly suggested to function by inhibiting DNA replication through the inactivation of ribonucleotide reductase and depleting deoxyribonucleoside triphosphate pools. Here, we show that hydroxyurea only transiently inhibits replication inEscherichia colibefore replication rapidly recovers and continues in the presence of the drug. The recovery of replication does not depend on alternative ribonucleotide reductases, translesion synthesis, or RecA. Further, we show that hydroxyurea toxicity is observed only in the presence of toxic intermediates that accumulate when hydroxyurea breaks down, damage DNA, and induce lethality. The results demonstrate that hydroxyurea toxicity is mediated indirectly by the formation of DNA damage, rather than by inhibition of replication or depletion of deoxyribonucleotide levels in the cell.

RECOVERY FROM DAMAGE INDUCED BY ACRIDINE PLUS NEAR-ULTRAVIOLET LIGHT IN ESCHERICHIA COLI

1982 ◽  
Vol 35 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Stephen Wagner ◽  
Abbe Feldman ◽  
Wallace Snipes
Keyword(s):  
Escherichia Coli ◽  
Ultraviolet Light ◽  
Near Ultraviolet
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