Magnetically sensitive light-induced reactions in cryptochrome are consistent with its proposed role as a magnetoreceptor

Proc Natl Acad Sci U S A · 2012 · Unclear · Insufficient evidence

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UnclearInsufficient evidencePaper 6719

The authors report that the kinetics and quantum yields of photo-induced flavin-tryptophan radical pairs in cryptochrome are magnetically sensitive. They describe the mechanistic origin of the magnetic field effect, its dependence on magnetic field strength, …

Study snapshot

PublicationProc Natl Acad Sci U S A · 2012

Study typeother

Reported directionUnclear

Evidence ratingInsufficient

Abstract

Among the biological phenomena that fall within the emerging field of "quantum biology" is the suggestion that magnetically sensitive chemical reactions are responsible for the magnetic compass of migratory birds. It has been proposed that transient radical pairs are formed by photo-induced electron transfer reactions in cryptochrome proteins and that their coherent spin dynamics are influenced by the geomagnetic field leading to changes in the quantum yield of the signaling state of the protein. Despite a variety of supporting evidence, it is still not clear whether cryptochromes have the properties required to respond to magnetic interactions orders of magnitude weaker than the thermal energy, k(B)T. Here we demonstrate that the kinetics and quantum yields of photo-induced flavin-tryptophan radical pairs in cryptochrome are indeed magnetically sensitive. The mechanistic origin of the magnetic field effect is clarified, its dependence on the strength of the magnetic field measured, and the rates of relevant spin-dependent, spin-independent, and spin-decoherence processes determined. We argue that cryptochrome is fit for purpose as a chemical magnetoreceptor.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeother

Effect directionunclear

PopulationNot supplied

Sample sizeNot supplied

ExposureNot supplied

Evidence strengthInsufficientConfidence: 74% · Peer reviewed: yes

Main findings

Outcomes measured

Kinetics of photo-induced flavin-tryptophan radical pairs in cryptochrome
Quantum yields of photo-induced flavin-tryptophan radical pairs in cryptochrome
Magnetic field dependence of the magnetic field effect
Rates of spin-dependent, spin-independent, and spin-decoherence processes

Limitations

No population or health outcomes described in the abstract
Magnetic field strength values and exposure conditions are not provided in the abstract
Study context appears mechanistic/biophysical; generalizability to in vivo magnetoreception is not established in the abstract

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": null,
    "source": "geomagnetic field / magnetic field (laboratory)",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Kinetics of photo-induced flavin-tryptophan radical pairs in cryptochrome",
    "Quantum yields of photo-induced flavin-tryptophan radical pairs in cryptochrome",
    "Magnetic field dependence of the magnetic field effect",
    "Rates of spin-dependent, spin-independent, and spin-decoherence processes"
  ],
  "main_findings": "The authors report that the kinetics and quantum yields of photo-induced flavin-tryptophan radical pairs in cryptochrome are magnetically sensitive. They describe the mechanistic origin of the magnetic field effect, its dependence on magnetic field strength, and determine rates of relevant spin-dependent, spin-independent, and spin-decoherence processes.",
  "effect_direction": "unclear",
  "limitations": [
    "No population or health outcomes described in the abstract",
    "Magnetic field strength values and exposure conditions are not provided in the abstract",
    "Study context appears mechanistic/biophysical; generalizability to in vivo magnetoreception is not established in the abstract"
  ],
  "evidence_strength": "insufficient",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "cryptochrome",
    "radical pair",
    "photo-induced electron transfer",
    "flavin-tryptophan radical pair",
    "magnetic field effect",
    "geomagnetic field",
    "spin dynamics",
    "quantum yield",
    "magnetoreception",
    "quantum biology"
  ],
  "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1073/pnas.1118959109
PubMed: 22421133

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