Cyanide Binding to cd1 Nitrite Reductase from Pseudomonas aeruginosa: Role of the Active-Site His369 in Ligand Stabilization

2002 ◽  
Vol 291 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Wenliang Sun ◽  
Marzia Arese ◽  
Maurizio Brunori ◽  
Didier Nurizzo ◽  
Kieron Brown ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Nitrite Reductase ◽  
Active Site ◽  
Cyanide Binding ◽  
Ligand Stabilization

scholarly journals The effect of haem ligands on the redox states of the hexa-haem nitrite reductase from Wolinella succinogenes

1990 ◽  
Vol 271 (1) ◽  
pp. 253-257 ◽  
Author(s):  
R S Blackmore ◽  
P M A Gadsby ◽  
C Greenwood ◽  
A J Thomson
Keyword(s):  
Ligand Binding ◽  
Nitrite Reductase ◽  
Active Site ◽  
Redox State ◽  
Stopped Flow ◽  
Ligand Binding Site ◽  
Wolinella Succinogenes ◽  
Redox States ◽  
Cyanide Binding

The nitrite reductase of Wolinella succinogenes containing six covalently bound haem groups has one haem group that will not reduce fully in the presence of excess Na2S2O4. The effect of the extrinsic ligands CO and cyanide on the redox state of this haem was studied by e.p.r. and magnetic c.d. spectroscopy. It was found that both ligands increased the extent of reduction of this haem group, and that in the case of CO binding the level of reduction was correlated with the extent of CO saturation of the enzyme. Stopped-flow studies of the effect of cyanide binding on the rate of dithionite reduction showed that the rate of reduction of the ligand-binding site was increased in the presence of cyanide. This suggests that reduction of the haem groups at the active site is thermodynamically unfavourable in the absence of an extrinsic ligand. The role of the ‘non-reducing’ haem group and the effect of ligands on this centre and on the rate of reduction are discussed in relation to the reduction of nitrite by this enzyme.

New insights into the activity of Pseudomonas aeruginosa cd1 nitrite reductase

2008 ◽  
Vol 36 (6) ◽  
pp. 1155-1159 ◽  
Author(s):  
Serena Rinaldo ◽  
Alessandro Arcovito ◽  
Giorgio Giardina ◽  
Nicoletta Castiglione ◽  
Maurizio Brunori ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Pseudomonas Aeruginosa ◽  
Nitrite Reductase ◽  
Nitrite Reduction ◽  
Nitrite Reductases ◽  
Cytochrome Cd1 ◽  
Haem Iron ◽  
Shed Light ◽  
Denitrification Process

The cytochrome cd1 nitrite reductases are enzymes that catalyse the reduction of nitrite to nitric oxide (NO) in the bacterial energy conversion denitrification process. These enzymes contain two different redox centres: one covalently bound c-haem, which is reduced by external donors, and one peculiar d1-haem, where catalysis occurs. In the present paper, we summarize the current understanding of the reaction of nitrite reduction in the light of the most recent results on the enzyme from Pseudomonas aeruginosa and discuss the differences between enzymes from different organisms. We have evidence that release of NO from the ferrous d1-haem occurs rapidly enough to be fully compatible with the turnover, in contrast with previous hypotheses, and that the substrate nitrite is able to displace NO from the d1-haem iron. These results shed light on the mechanistic details of the activity of cd1 nitrite reductases and on the biological role of the d1-haem, whose presence in this class of enzymes has to date been unexplained.

scholarly journals Structure of heme d 1-free cd 1 nitrite reductase NirS

2020 ◽  
Vol 76 (6) ◽  
pp. 250-256
Author(s):  
Thomas Klünemann ◽  
Wulf Blankenfeldt
Keyword(s):  
Nitric Oxide ◽  
Pseudomonas Aeruginosa ◽  
Nitrite Reductase ◽  
Active Site ◽  
Opportunistic Pathogen ◽  
Active Enzyme ◽  
Free Form ◽  
Nitrate Respiration ◽  
Gram Negative ◽  
Open Conformation

A key step in anaerobic nitrate respiration is the reduction of nitrite to nitric oxide, which is catalysed by the cd 1 nitrite reductase NirS in, for example, the Gram-negative opportunistic pathogen Pseudomonas aeruginosa. Each subunit of this homodimeric enzyme consists of a cytochrome c domain and an eight-bladed β-propeller that binds the uncommon isobacteriochlorin heme d 1 as an essential part of its active site. Although NirS has been well studied mechanistically and structurally, the focus of previous studies has been on the active heme d 1-bound form. The heme d 1-free form of NirS reported here, which represents a premature state of the reductase, adopts an open conformation with the cytochrome c domains moved away from each other with respect to the active enzyme. Further, the movement of a loop around Trp498 seems to be related to a widening of the propeller, allowing easier access to the heme d 1-binding side. Finally, a possible link between the open conformation of NirS and flagella formation in P. aeruginosa is discussed.

Role of the active-site cysteine of Pseudomonas aeruginosa azurin. Crystal structure analysis of the CuII(Cys112Asp) protein

1997 ◽  
Vol 2 (4) ◽  
pp. 464-469 ◽  
Author(s):  
Salem Faham ◽  
Tadashi J. Mizoguchi ◽  
Elinor T. Adman ◽  
Harry B. Gray ◽  
John H. Richards ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Pseudomonas Aeruginosa ◽  
Structure Analysis ◽  
Active Site ◽  
Crystal Structure Analysis ◽  
Active Site Cysteine

scholarly journals Structure of heme d1-free cd1 nitrite reductase NirS

2020 ◽  
Author(s):  
Thomas Klünemann ◽  
Wulf Blankenfeldt
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Nitrite Reductase ◽  
Active Site ◽  
Opportunistic Pathogen ◽  
Free Form ◽  
Nitrate Respiration ◽  
Gram Negative ◽  
Open Conformation ◽  
Heme D1 ◽  
Insight Into

AbstractA key step in anaerobic nitrate respiration is the reduction of nitrite to nitric oxide, which is catalysed by cd1 nitrite reductase NirS in e.g. the gram-negative opportunistic pathogen Pseudomonas aeruginosa. Each subunit of this homodimeric enzyme consists of a cytochrome c domain and an eight-bladed β-propeller that binds the uncommon isobacteriochlorin heme d1 as an essential part of its active site. Although NirS is mechanistically and structurally well studied, the focus of previous studies has been on the active, heme d1-bound form. The heme d1-free form of NirS reported here, representing a premature state of the reductase, adopts an open conformation with the cytochrome c domains moved away from each other with respect to the active enzyme. Further, movement of a loop around W498 seems to be related to a widening of the propeller, allowing easier access to the heme d1 binding side. Finally, a possible link between the open conformation of NirS and flagella formation in P. aeruginosa is discussed.SynopsisThe crystal structure of heme d1-free cd1 nitrite reductase NirS from Pseudomonas aeruginosa has been determined and provides insight into a premature form of the enzyme.

scholarly journals Essential Role of Transcription Factor Nuclear Factor-κB in Regulation of Interleukin-8 Gene Expression by Nitrite Reductase from Pseudomonas aeruginosa in Respiratory Epithelial Cells

1999 ◽  
Vol 67 (8) ◽  
pp. 3872-3878 ◽  
Author(s):  
Naoki Mori ◽  
Kazunori Oishi ◽  
Borann Sar ◽  
Naofumi Mukaida ◽  
Tsuyoshi Nagatake ◽  
...  
Keyword(s):  
Gene Expression ◽  
Pseudomonas Aeruginosa ◽  
Epithelial Cells ◽  
Nitrite Reductase ◽  
Critical Role ◽  
Nuclear Factor Κb ◽  
Interleukin 8 ◽  
Nuclear Factor ◽  
Respiratory Cells

ABSTRACT Persistent infection with Pseudomonas aeruginosaincreases interleukin-8 (IL-8) levels and causes dense neutrophil infiltrations in the airways of patients with chronic airway diseases. Recently, we have reported that nitrite reductase from P. aeruginosa induces the production of IL-8 in respiratory cells, including bronchial epithelial cells. To determine the molecular mechanism(s) of nitrite reductase-induced IL-8 expression in respiratory cells, A549 epithelial cells were transfected with plasmids containing serial deletions of the 5′-flanking region of the IL-8 gene and then exposed to nitrite reductase. Nitrite reductase significantly enhanced IL-8 gene promoter-driven reporter activity. This increased IL-8 gene expression was inhibited by mutating the nuclear factor-κB (NF-κB) binding element. Nitrite reductase enhanced nuclear localization of the NF-κB binding complex. Furthermore, nitrite reductase induced the degradation of IκBα, the major cytoplasmic inhibitor of NF-κB, and the expression of IκBα mRNA. These data support the critical role of the activation of NF-κB in nitrite reductase-induced IL-8 gene expression in airway epithelium.

scholarly journals An investigation of the ligand-binding properties of Pseudomonas aeruginosa nitrite reductase

1986 ◽  
Vol 233 (3) ◽  
pp. 893-898 ◽  
Author(s):  
J Sutherland ◽  
C Greenwood ◽  
J Peterson ◽  
A J Thomson
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Conformational Changes ◽  
Nitrite Reductase ◽  
Magnetic Circular Dichroism ◽  
Binding Properties ◽  
Reduction Processes ◽  
Axial Ligands ◽  
Protein Conformational Changes ◽  
Cyanide Binding ◽  
Magnetic Circular Dichroism Spectra

The low-temperature e.p.r. and m.c.d. (magnetic-circular-dichroism) spectra of Pseudomonas aeruginosa nitrite reductase, together with those of its partially and fully cyanide-bound derivatives, were investigated. The m.c.d. spectra in the range 600-2000 nm indicate that the native axial ligands to haem c are histidine and methionine, and furthermore that it is the methionine ligand that must be displaced before cyanide binding at this haem. The m.c.d. spectra in the range 1000-2000 nm contain no charge-transfer bands arising from low-spin ferric haem d1, a chlorin. New optical transitions in the region 700-850 nm were found for the cyanide adduct of haem d1. The g-values of haem d1 in the native enzyme are 2.51, 2.43 and 1.71, suggesting co-ordination by two histidine ligands in the oxidized state. There is clear evidence in the e.p.r. data of an interaction between the c and d1 haem groups. This is not apparent in the optical spectra. The results are interpreted in terms of haem groups that are remote from each other, their interaction being mediated through protein conformational changes. The possible implications of this in relation to reduction processes catalysed by the enzyme are considered.

Role of rhizobia in suppressing the root rot and root knot disease of chili used alone or with Pseudomonas aeruginosa

2019 ◽  
Vol 52 (3) ◽  
Author(s):  
Gulnaz Parveen ◽  
Faizah Urooj ◽  
Hafiza Asma Shafique ◽  
Afshan Rahman ◽  
Syed Ehteshamul Haque
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Root Rot
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