Reduced flavin : NMR investigation of N(5)-H exchange mechanism, estimation of ionisation constants and assessment of properties as biological catalyst

Macheroux, Peter; Ghisla, Sandro; Sanner, Christoph; Rüterjans, Heinz; Müller, Franz

Reduced flavin : NMR investigation of N(5)-H exchange mechanism, estimation of ionisation constants and assessment of properties as biological catalyst

Dateien

Reduced_flavin.pdfGröße: 682.41 KBDownloads: 513

Datum

2005

Autor:innen

Macheroux, Peter

Ghisla, Sandro

Sanner, Christoph

Rüterjans, Heinz

Müller, Franz

Open Access-Veröffentlichung

Open Access Green

Sammlungen

Biologie

Publikationstyp

Zeitschriftenartikel

Publikationsstatus

Published

Erschienen in

BMC Biochemistry. 2005, 6, 26. ISSN 1471-2091. eISSN 1471-2091. Available under: doi: 10.1186/1471-2091-6-26

Zusammenfassung

Background: The flavin in its FMN and FAD forms is a versatile cofactor that is involved in catalysis of most disparate types of biological reactions. These include redox reactions such as dehydrogenations, activation of dioxygen, electron transfer, bioluminescence, blue light reception, photobiochemistry (as in photolyases), redox signaling etc. Recently, hitherto unrecognized types of biological reactions have been uncovered that do not involve redox shuffles, and might involve the reduced form of the flavin as a catalyst. The present work addresses properties of reduced flavin relevant in this context.
Results: N(5)-H exchange reactions of the flavin reduced form and its pH dependence were studied using the 15N-NMR-signals of 15N-enriched, reduced flavin in the pH range from 5 to 12. The chemical shifts of the N(3) and N(5) resonances are not affected to a relevant extent in this pH range. This contrasts with the multiplicity of the N(5)-resonance, which strongly depends on pH. It is a doublet between pH 8.45 and 10.25 that coalesces into a singlet at lower and higher pH values. From the line width of the 15N(5) signal the pH-dependent rate of hydrogen exchange was deduced. The multiplicity of the 15N(5) signal and the proton exchange rates are little dependent on the buffer system used.
Conclusion: The exchange rates allow an estimation of the pKa value of N(5)-H deprotonation in reduced flavin to be ≥ 20. This value imposes specific constraints for mechanisms of flavoprotein catalysis based on this process. On the other hand the pK ≈ 4 for N(5)-H protonation (to form N(5)+-H2) would be consistent with a role of N(5)-H as a base.

Fachgebiet (DDC)

570 Biowissenschaften, Biologie

Zitieren

ISO 690

MACHEROUX, Peter, Sandro GHISLA, Christoph SANNER, Heinz RÜTERJANS, Franz MÜLLER, 2005. Reduced flavin : NMR investigation of N(5)-H exchange mechanism, estimation of ionisation constants and assessment of properties as biological catalyst. In: BMC Biochemistry. 2005, 6, 26. ISSN 1471-2091. eISSN 1471-2091. Available under: doi: 10.1186/1471-2091-6-26

BibTex

@article{Macheroux2005Reduc-6687,
  year={2005},
  doi={10.1186/1471-2091-6-26},
  title={Reduced flavin : NMR investigation of N(5)-H exchange mechanism, estimation of ionisation constants and assessment of properties as biological catalyst},
  volume={6},
  issn={1471-2091},
  journal={BMC Biochemistry},
  author={Macheroux, Peter and Ghisla, Sandro and Sanner, Christoph and Rüterjans, Heinz and Müller, Franz},
  note={Article Number: 26}
}

RDF

<rdf:RDF
    xmlns:dcterms="http://purl.org/dc/terms/"
    xmlns:dc="http://purl.org/dc/elements/1.1/"
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:bibo="http://purl.org/ontology/bibo/"
    xmlns:dspace="http://digital-repositories.org/ontologies/dspace/0.1.0#"
    xmlns:foaf="http://xmlns.com/foaf/0.1/"
    xmlns:void="http://rdfs.org/ns/void#"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema#" > 
  <rdf:Description rdf:about="https://kops.uni-konstanz.de/server/rdf/resource/123456789/6687">
    <bibo:uri rdf:resource="http://kops.uni-konstanz.de/handle/123456789/6687"/>
    <dc:rights>Attribution-NonCommercial-NoDerivs 2.0 Generic</dc:rights>
    <dc:contributor>Rüterjans, Heinz</dc:contributor>
    <dcterms:available rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2011-03-24T17:28:22Z</dcterms:available>
    <dspace:hasBitstream rdf:resource="https://kops.uni-konstanz.de/bitstream/123456789/6687/1/Reduced_flavin.pdf"/>
    <dc:creator>Rüterjans, Heinz</dc:creator>
    <dcterms:issued>2005</dcterms:issued>
    <dc:language>eng</dc:language>
    <dc:creator>Müller, Franz</dc:creator>
    <dc:contributor>Macheroux, Peter</dc:contributor>
    <dcterms:abstract xml:lang="eng">Background: The flavin in its FMN and FAD forms is a versatile cofactor that is involved in catalysis of most disparate types of biological reactions. These include redox reactions such as dehydrogenations, activation of dioxygen, electron transfer, bioluminescence, blue light reception, photobiochemistry (as in photolyases), redox signaling etc. Recently, hitherto unrecognized types of biological reactions have been uncovered that do not involve redox shuffles, and might involve the reduced form of the flavin as a catalyst. The present work addresses properties of reduced flavin relevant in this context.&lt;br /&gt;Results: N(5)-H exchange reactions of the flavin reduced form and its pH dependence were studied using the 15N-NMR-signals of 15N-enriched, reduced flavin in the pH range from 5 to 12. The chemical shifts of the N(3) and N(5) resonances are not affected to a relevant extent in this pH range. This contrasts with the multiplicity of the N(5)-resonance, which strongly depends on pH. It is a doublet between pH 8.45 and 10.25 that coalesces into a singlet at lower and higher pH values. From the line width of the 15N(5) signal the pH-dependent rate of hydrogen exchange was deduced. The multiplicity of the 15N(5) signal and the proton exchange rates are little dependent on the buffer system used.&lt;br /&gt;Conclusion: The exchange rates allow an estimation of the pKa value of N(5)-H deprotonation in reduced flavin to be ≥ 20. This value imposes specific constraints for mechanisms of flavoprotein catalysis based on this process. On the other hand the pK ≈ 4 for N(5)-H protonation (to form N(5)+-H2) would be consistent with a role of N(5)-H as a base.</dcterms:abstract>
    <dcterms:isPartOf rdf:resource="https://kops.uni-konstanz.de/server/rdf/resource/123456789/28"/>
    <dc:contributor>Sanner, Christoph</dc:contributor>
    <dspace:isPartOfCollection rdf:resource="https://kops.uni-konstanz.de/server/rdf/resource/123456789/28"/>
    <dc:creator>Ghisla, Sandro</dc:creator>
    <void:sparqlEndpoint rdf:resource="http://localhost/fuseki/dspace/sparql"/>
    <dc:creator>Sanner, Christoph</dc:creator>
    <dcterms:bibliographicCitation>First publ. in: BMC Biochemistry (2005), 6:26</dcterms:bibliographicCitation>
    <dc:date rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2011-03-24T17:28:22Z</dc:date>
    <dc:contributor>Müller, Franz</dc:contributor>
    <dc:format>application/pdf</dc:format>
    <dcterms:hasPart rdf:resource="https://kops.uni-konstanz.de/bitstream/123456789/6687/1/Reduced_flavin.pdf"/>
    <dcterms:rights rdf:resource="http://creativecommons.org/licenses/by-nc-nd/2.0/"/>
    <foaf:homepage rdf:resource="http://localhost:8080/"/>
    <dcterms:title>Reduced flavin : NMR investigation of N(5)-H exchange mechanism, estimation of ionisation constants and assessment of properties as biological catalyst</dcterms:title>
    <dc:creator>Macheroux, Peter</dc:creator>
    <dc:contributor>Ghisla, Sandro</dc:contributor>
  </rdf:Description>
</rdf:RDF>

Universitätsbibliographie

Ja