Spectroscopic Characterization of Radical Pair Photochemistry in Nonmigratory Avian Cryptochromes: Magnetic Field Effects in <i>Gg</i>Cry4a.

ABSTRACT: The magnetic compass sensor in night-migratory songbirds is thought to be a flavin-tryptophan radical pair formed by blue-light excitation of the protein cryptochrome-4a (Cry4a) localized in photoreceptor cells in the birds' retinas. The effects of applied magnetic fields on the photochemistry of purified Cry4a from the migratory European robin are well characterized, but it is less clear what, if anything, distinguishes the magnetic responses of the Cry4a proteins from migratory and nonmigratory species. We present here a detailed study of the magnetic sensitivity of Cry4a from the nonmigratory chicken. The wild-type protein is compared with two mutants in which either Arg317 or Glu320, both close to the tryptophan radical, were replaced by the amino acids Cys and Lys, respectively, found

SUBMITTER: Gravell J 

PROVIDER: S-EPMC12272691 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature