Photodissociation of nitric oxide from the non-heme iron center activates nitrile hydratase from Rhodococcus sp. N-771: FTIR and resonance Raman evidence

Noguchi, T.; Odaka, Masafumi; Hoshino, Mikio; Tsujimura, Maki; Inoue, Yorinao; Endo, Itaru

doi:10.1016/s0162-0134(97)80201-2

Cited by 4 publications

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“…These data are consistent with the accumulation of an and were attributed to an increase in electron donation from the axial thiolate ligand to the Fe 3ϩ ion to compensate for the -accepting behavior of the bound ligand (20,21). Similarly, the absorbance band observed at 450 nm, which has also been assigned as an Fe 3ϩ 4S LMCT band based on resonance Raman data and magnetic circular dichroism model complex data (17,19), increases in intensity upon substrate binding. Taken together, these data indicate that the observed enzyme-substrate complex is the result of the direct ligation of a nitrile to the active site low spin Fe 3ϩ center, which forms an Fe 3ϩ -nitrile intermediate species.…”

supporting

confidence: 78%

“…Direct coordination of NO to the low spin Fe 3ϩ active site was confirmed by EPR and resonance Raman data, which suggested that NO displaces the axial water molecule, forming an Fe 3ϩ -NO complex that is inactive. The Fe 3ϩ 4S LMCT band observed at ϳ700 nm in resting iron-type NHase is not observed in NO-inhibited NHase enzymes but reappears upon light-induced activation (19,22). However, in the enzyme-substrate intermediate complex, the Fe 3ϩ 4S LMCT band at ϳ650 nm and a strong absorption at 375 nm are observed.…”

mentioning

confidence: 88%

“…In the presence of NO, iron-type NHases show strong absorbance at 370 nm corresponding to an Fe 3ϩ 4S LMCT band that results from the direct coordination of the NO to the Fe 3ϩ active site (19,22). Direct coordination of NO to the low spin Fe 3ϩ active site was confirmed by EPR and resonance Raman data, which suggested that NO displaces the axial water molecule, forming an Fe 3ϩ -NO complex that is inactive.…”

mentioning

confidence: 93%

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Identification of an Active Site-bound Nitrile Hydratase Intermediate through Single Turnover Stopped-flow Spectroscopy

Gumataotao

Kuhn

Hajnas

et al. 2013

Journal of Biological Chemistry

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Background:No direct evidence exists for the direct coordination of nitrile to the Fe 3ϩ active site in nitrile hydratases. Results: The first Fe 3ϩ -nitrile intermediate species is reported using stopped-flow spectroscopy. Conclusion: These data establish that the direct ligation of the nitrile substrate occurs during catalytic turnover. Significance: Understanding the catalytic mechanism of nitrile hydratases is critical to harness their bioremediation and industrial potential.

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confidence: 78%

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confidence: 88%

mentioning

confidence: 93%

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Identification of an Active Site-bound Nitrile Hydratase Intermediate through Single Turnover Stopped-flow Spectroscopy

Gumataotao

Kuhn

Hajnas

et al. 2013

Journal of Biological Chemistry

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“…In vivo, this enzyme loses the catalytic activity through aerobic incubation in the dark, but immediately recovers the activity by light irradiation in vivo and in vitro~photoactivation!. The iron center in the inactive state is associated with an endogenous nitric oxide~NO!, and the NO molecule dissociates immediately after light irradiatioñ Noguchi et al, 1995Noguchi et al, , 1996Odaka et al, 1997!. This characteristic is likely to be common in all iron-type NHases~Bonnet et al, 1997!. Recently, the crystal structures of NHase in the nitrosylated and photoactivated states were determined at resolutions of 1.7 Å~Naga-shima et al, 1998!…”

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confidence: 99%

Post‐translational modification is essential for catalytic activity of nitrile hydratase

et al. 2000

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Nitrile hydratase from Rhodococcus sp. N-771 is an ab heterodimer with a nonheme ferric iron in the catalytic center. In the catalytic center, aCys112 and aCys114 are modified to a cysteine sulfinic acid~Cys-SO 2 H! and a cysteine sulfenic acid~Cys-SOH!, respectively. To understand the function and the biogenic mechanism of these modified residues, we reconstituted the nitrile hydratase from recombinant unmodified subunits. The ab complex reconstituted under argon exhibited no activity. However, it gradually gained the enzymatic activity through aerobic incubation. ESI-LC0MS analysis showed that the anaerobically reconstituted ab complex did not have the modification of aCys112-SO 2 H and aerobic incubation induced the modification. The activity of the reconstituted ab complex correlated with the amount of aCys112-SO 2 H. Furthermore, ESI-LC0MS analyses of the tryptic digest of the reconstituted complex, removed of ferric iron at low pH and carboxamidomethylated without reduction, suggested that aCys114 is modified to Cys-SOH together with the sulfinic acid modification of aCys112. These results suggest that aCys112 and aCys114 are spontaneously oxidized to Cys-SO 2 H and Cys-SOH, respectively, and aCys112-SO 2 H is responsible for the catalytic activity solely or in combination with aCys114-SOH.

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“…However, illumination could recover such loss of catalytic activity. Spectroscopic studies demonstrated that the replacement of a NO molecule by water or hydroxide contributes to the recovery of Fe-NHase activity and changes the enzyme from the inactive form to active form (Noguchi et al, 1996;Odaka et al, 1997;Popescu et al, 2001).…”

Section: Fe-type Nhasementioning

confidence: 99%

Recent Advances and Promises in Nitrile Hydratase: From Mechanism to Industrial Applications

Cheng

Xia

Zhou

2020

Front. Bioeng. Biotechnol.

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Nitrile hydratase (NHase, EC 4.2.1.84) is one type of metalloenzyme participating in the biotransformation of nitriles into amides. Given its catalytic specificity in amide production and eco-friendliness, NHase has overwhelmed its chemical counterpart during the past few decades. However, unclear catalytic mechanism, low thermostablity, and narrow substrate specificity limit the further application of NHase. During the past few years, numerous studies on the theoretical and industrial aspects of NHase have advanced the development of this green catalyst. This review critically focuses on NHase research from recent years, including the natural distribution, gene types, posttranslational modifications, expression, proposed catalytic mechanism, biochemical properties, and potential applications of NHase. The developments of NHase described here are not only useful for further application of NHase, but also beneficial for the development of the fields of biocatalysis and biotransformation.

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Photodissociation of nitric oxide from the non-heme iron center activates nitrile hydratase from Rhodococcus sp. N-771: FTIR and resonance Raman evidence

Cited by 4 publications

References 0 publications

Identification of an Active Site-bound Nitrile Hydratase Intermediate through Single Turnover Stopped-flow Spectroscopy

Identification of an Active Site-bound Nitrile Hydratase Intermediate through Single Turnover Stopped-flow Spectroscopy

Post‐translational modification is essential for catalytic activity of nitrile hydratase

Recent Advances and Promises in Nitrile Hydratase: From Mechanism to Industrial Applications

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