Evidence map›Paper›PMID 27136534›Full record

ArticleInternational journal of molecular sciences2016

Residues in the Distal Heme Pocket of Arabidopsis Non-Symbiotic Hemoglobins: Implication for Nitrite Reductase Activity.

Nitin Kumar, Alessandra Astegno, Jian Chen, Alejandro Giorgetti, Paola Dominici

Open access · goldAbstract read
In one paragraph

Article in International journal of molecular sciences, 2016. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers.

0numbers the graph read from it
0cells of the map it votes in
6citing papers in PubMed
1.1field-weighted citation impact, top 24% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

6 citing papers in PubMed, 13 citations in OpenAlex.

  1. Hemoglobin as an oxygen gasoreceptor.Acta biochimica Polonica · 2025
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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors at 1 institution in 2 countries.

Nitin KumarHypertension & Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, MI 48202, USA. nkumar3@hfhs.org.
Alessandra AstegnoDepartment of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy. alessandra.astegno@univr.it.
Jian ChenDepartment of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy. jianchen0722@gmail.com.
Alejandro GiorgettiDepartment of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy. alejandro.giorgetti@univr.it.
Paola DominiciDepartment of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy. paola.dominici@univr.it.
University of Verona · IT

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

It is well-established that plant hemoglobins (Hbs) are involved in nitric oxide (NO) metabolism via NO dioxygenase and/or nitrite reductase activity. The ferrous-deoxy Arabidopsis Hb1 and Hb2 (AHb1 and AHb2) have been shown to reduce nitrite to NO under hypoxia. Here, to test the hypothesis that a six- to five-coordinate heme iron transition might mediate the control of the nitrite reduction rate, we examined distal pocket mutants of AHb1 and AHb2 for nitrite reductase activity, NO production and spectroscopic features. Absorption spectra of AHbs distal histidine mutants showed that AHb1 mutant (H69L) is a stable pentacoordinate high-spin species in both ferrous and ferric states, whereas heme iron in AHb2 mutant (H66L) is hexacoordinated low-spin with Lys69 as the sixth ligand. The bimolecular rate constants for nitrite reduction to NO were 13.3 ± 0.40, 7.3 ± 0.5, 10.6 ± 0.8 and 171.90 ± 9.00 M(-1)·s(-1) for AHb1, AHb2, AHb1 H69L and AHb2 H66L, respectively, at pH 7.4 and 25 °C. Consistent with the reductase activity, the amount of NO detected by chemiluminescence was significantly higher in the AHb2 H66L mutant. Our data indicate that nitrite reductase activity is determined not only by heme coordination, but also by a unique distal heme pocket in each AHb.

Indexed as

Amino Acid SequenceAnimalsArabidopsisArabidopsis ProteinsHemeHemoglobinsHydrogen-Ion ConcentrationHydrogen PeroxideLuminescent MeasurementsMolecular Sequence DataMutagenesisNitric OxideNitrite ReductasesOxidation-ReductionPeroxynitrous AcidSequence AlignmentArabidopsis ProteinsHemeHemoglobinsHydrogen PeroxideNitric OxideNitrite ReductasesPeroxynitrous AcidArabidopsis hemoglobinsdistal cavityhypoxianitrite reduction

Identifiers

PMID27136534
PMCPMC4881466
OpenAlexW2344184203

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.