scholarly journals Involvement of products of the nrfEFG genes in the covalent attachment of haem c to a novel cysteine-lysine motif in the cytochrome c552 nitrite reductase from Escherichia coli

2002 ◽  
Vol 28 (1) ◽  
pp. 205-216 ◽  
Author(s):  
D. J. Eaves ◽  
J. Grove ◽  
W. Staudenmann ◽  
P. James ◽  
R. K. Poole ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Nitrite Reductase ◽  
Covalent Attachment ◽  
Cytochrome C552

scholarly journals Variation of the axial haem ligands and haem-binding motif as a probe of the Escherichia coli c-type cytochrome maturation (Ccm) system

2003 ◽  
Vol 375 (3) ◽  
pp. 721-728 ◽  
Author(s):  
James W. A. ALLEN ◽  
Stuart J. FERGUSON
Keyword(s):  
Escherichia Coli ◽  
Cytochrome C ◽  
Covalent Attachment ◽  
Binding Motif ◽  
Cytochrome C Maturation ◽  
Cytochromes C ◽  
Cytochrome C552 ◽  
Haem Iron ◽  
Made In ◽  
Uncatalysed Reaction

Cytochromes c are typically characterized by the covalent attachment of haem to polypeptide through two thioether bonds with the cysteine residues of a Cys-Xaa-Xaa-Cys-His peptide motif. In many Gram-negative bacteria, the haem is attached to the polypeptide by the periplasmically functioning cytochrome c maturation (Ccm) proteins. Exceptionally, Hydrogenobacter thermophilus cytochrome c552 can be expressed as a stable holocytochrome both in the cytoplasm of Escherichia coli in an apparently uncatalysed reaction and also in the periplasm in a Ccm-mediated reaction. In the present study we show that a Met60→Ala variant of c552, which does not have the usual distal methionine ligand to the haem iron of the mature cytochrome, can be made in the periplasm by the Ccm system. However, no holocytochrome could be detected when this variant was expressed cytoplasmically. These data highlight differences between the two modes of cytochrome c assembly. In addition, we report investigations of haem attachment to cytochromes altered to have the special Cys-Trp-Ser-Cys-Lys haem-binding motif, and Cys-Trp-Ser-Cys-His and Cys-Trp-Ala-Cys-His analogues, of the active-site haem of nitrite reductase NrfA.

The nrfEFG gene products are required for the activity of the cytochrome c552 nitrite reductase from Escherichia coli

1998 ◽  
Vol 26 (3) ◽  
pp. S216-S216 ◽  
Author(s):  
D. Eaves ◽  
J. Grove ◽  
W. Staudenmann ◽  
P. James ◽  
R. Poole ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Nitrite Reductase ◽  
Gene Products ◽  
Cytochrome C552

scholarly journals SERR Spectroelectrochemical Study of Cytochrome cd1 Nitrite Reductase Co-Immobilized with Physiological Redox Partner Cytochrome c552 on Biocompatible Metal Electrodes

PLoS ONE ◽  
2015 ◽  
Vol 10 (6) ◽  
pp. e0129940 ◽  
Author(s):  
Célia M. Silveira ◽  
Pedro O. Quintas ◽  
Isabel Moura ◽  
José J. G. Moura ◽  
Peter Hildebrandt ◽  
...  
Keyword(s):  
Nitrite Reductase ◽  
Metal Electrodes ◽  
Redox Partner ◽  
Cytochrome C552 ◽  
Cytochrome Cd1

scholarly journals Functional Analysis of the Acinetobacter baumannii XerC and XerD Site-Specific Recombinases: Potential Role in Dissemination of Resistance Genes

Antibiotics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 405
Author(s):  
David L. Lin ◽  
German M. Traglia ◽  
Rachel Baker ◽  
David J. Sherratt ◽  
Maria Soledad Ramirez ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Functional Analysis ◽  
Acinetobacter Baumannii ◽  
Potential Role ◽  
Covalent Attachment ◽  
Recombination Reaction ◽  
Site Specific ◽  
Site Specific Recombination ◽  
E Coli ◽  
Resistant Genes

Modules composed of a resistance gene flanked by Xer site-specific recombination sites, the vast majority of which were found in Acinetobacter baumannii, are thought to behave as elements that facilitate horizontal dissemination. The A. baumannii xerC and xerD genes were cloned, and the recombinant clones used to complement the cognate Escherichia coli mutants. The complemented strains supported the resolution of plasmid dimers, and, as is the case with E. coli and Klebsiella pneumoniae plasmids, the activity was enhanced when the cells were grown in a low osmolarity growth medium. Binding experiments showed that the partially purified A. baumannii XerC and XerD proteins (XerCAb and XerDAb) bound synthetic Xer site-specific recombination sites, some of them with a nucleotide sequence deduced from existing A. baumannii plasmids. Incubation with suicide substrates resulted in the covalent attachment of DNA to a recombinase, probably XerCAb, indicating that the first step in the recombination reaction took place. The results described show that XerCAb and XerDAb are functional proteins and support the hypothesis that they participate in horizontal dissemination of resistant genes among bacteria.

scholarly journals The steady state kinetics of the NADH-dependent nitrite reductase from Escherichia coli K12. The reduction of single-electron acceptors

1982 ◽  
Vol 203 (2) ◽  
pp. 505-510 ◽  
Author(s):  
R H Jackson ◽  
J A Cole ◽  
A Cornish-Bowden
Keyword(s):  
Escherichia Coli ◽  
Cytochrome C ◽  
Nitrite Reductase ◽  
Maximum Velocity ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Steady State Kinetics ◽  
Cytochrome C Reduction ◽  
Pattern Of Variation ◽  
Rate Limiting

The kinetic characteristics of the diaphorase activities associated with the NADH-dependent nitrite reductase (EC 1.6.6.4) from Escherichia coli have been determined. The values of the apparent maximum velocity are similar for the reduction of Fe(CN)6(3)-and mammalian cytochrome c by NADH. These reactions may therefore have the same rate-limiting step. NAD+ activates NADH-dependent reduction of cytochrome c, and the apparent maximum velocity for this substrate increases more sharply with the concentration of NAD+ than for hydroxylamine. The simplest explanation is that NAD+ activation of hydroxylamine reduction derives solely from activation of steps involved in the reduction of cytochrome c, a flavin-mediated reaction, but these steps are only partly rate-limiting for the reduction of hydroxylamine. At 0.5 mM-NAD+, the apparent maximum velocity was 2.3 times higher for 0.1 mM-cytochrome c as substrate than for 100 mM-hydroxylamine, suggesting that the rate-limiting step during hydroxylamine reduction is a step that is not involved in cytochrome c reduction. A scheme is proposed that can account for the pattern of variation with [NAD+] of the Michaelis-Menten parameters for hydroxylamine and for NADH with hydroxylamine or cytochrome c as oxidized substrate.

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