Evidence map›Paper›PMID 26499393›Full record

ArticleJournal of inorganic biochemistry2015

pH dependence of cyanide and imidazole binding to the heme domains of Sinorhizobium meliloti and Bradyrhizobium japonicum FixL.

Anil K Bidwai, Angela J Ahrendt, John S Sullivan, Lidia B Vitello, James E Erman

Abstract read
In one paragraph

Article in Journal of inorganic biochemistry, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

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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

2 citing papers in PubMed.

  1. Structural Basis of a Novel Heme Binding Bacterial One-Component Switch.bioRxiv : the preprint server for biology · 2026
    Article
  2. Article
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.

Anil K BidwaiDepartment of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL 60115, United States of America.
Angela J AhrendtDepartment of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL 60115, United States of America.
John S SullivanDepartment of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL 60115, United States of America.
Lidia B VitelloDepartment of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL 60115, United States of America.
James E ErmanDepartment of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL 60115, United States of America. Electronic address: jerman@niu.edu.

Funding

ELECTRON TRANSFER IN DYNAMIC PROTEIN COMPLEXESR15GM059740 · NIGMS · NORTHERN ILLINOIS UNIVERSITY · PI ERMAN, JAMES E · 1999 to 2009
$573k
NIGMS NIH HHS R15 GM059740NIGMS NIH HHS R15 GM59740
6 · The paper itself

Abstract

Equilibrium and kinetic properties of cyanide and imidazole binding to the heme domains of Sinorhizobium meliloti and Bradyrhizobium japonicum FixL (SmFixLH and BjFixLH) have been investigated between pH5 and 11. KD determinations were made at integral pH values, with the strongest binding at pH9 for both ligands. KD for the cyanide complexes of BjFixLH and SmFixLH is 0.15±0.09 and 0.50±0.20μM, respectively, and 0.70±0.01mM for imido-BjFixLH. The association rate constants are pH dependent with maximum values of 443±8 and 252±61M(-1)s(-1) for cyano complexes of BjFixLH and SmFixLH and (5.0±0.3)×10(4) and (7.0±1.4)×10(4)M(-1)s(-1) for the imidazole complexes. The dissociation rate constants are essentially independent of pH above pH5; (1.2±0.3)×10(-4) and (1.7±0.3)×10(-4)s(-1) for the cyano complexes of BjFixLH and SmFixLH, and (73±19) and (77±14) s(-1) for the imidazole complexes. Two ionizable groups in FixLH affect the rate of ligand binding. The more acidic group, identified as the heme 6 propionic acid, has a pKa of 7.6±0.2 in BjFixLH and 6.8±0.2 in SmFixLH. The second ionization is due to formation of hydroxy-FixLH with pKa values of 9.64±0.05 for BjFixLH and 9.61±0.05 for SmFixLH. Imidazole binding is limited by the rate of heme pocket opening with maximum observed values of 680 and 1270s(-1) for BjFixLH and SmFixLH, respectively.

Indexed as

Bacterial ProteinsBradyrhizobiumCyanidesHemeHemeproteinsHistidine KinaseHydrogen-Ion ConcentrationIronKineticsLigandsNitroimidazolesPoint MutationProtein BindingProtein DomainsSinorhizobium meliloti4-nitroimidazoleBacterial ProteinsCyanidesFixL protein, BacteriaHemeHemeproteinsHistidine KinaseIronLigandsNitroimidazolesCyanide bindingEquilibrium dissociation constantFixLHeme domainsImidazole bindingKinetics

Identifiers

PMID26499393
PMCPMC4690814

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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.