Biophysical Society Thematic Meeting | Hamburg 2022

Biophysics at the Dawn of Exascale Computers

Poster Abstracts

20-POS Board 20 STUCTURAL AND DYNAMIC CHARACTERIZATION OF AVIAN CRYPTOCRHOME 4 Maja Hanic 1 ; Anders Frederiksen 1 ; Fabian Schuhmann 1 ; Ilia Solov'yov 1 ;

1 Carl von Ossietzky University of Oldenburg, Department of physics, Oldenburg, Germany It is remarkable that the inclination angle of the Earth’s magnetic field vector can be used by birds as a source of a geomagnetic compass. Since the geomagnetic field penetrates biological materials the sensor for the magnetic field could be located anywhere inside an animal’s body. Protein that is believed to be involved in magnetic field sensing is called cryptochrome (Cry). Crys are photoreceptors that are known to regulate the entrainment of the circadian clock in plants and animals. Cry4 in particular was found in the outer segment of double cone cells and long wavelength single cones of birds’ eye and was shown to possess unique biochemical properties, unlike other members of the cryptochrome family, making it the best candidate for a magnetic field receptor in migratory birds. To understand the foundation of cryptochrome magnetic field sensing and unravel its biophysics it is imperative to have the structure of the protein. Currently the only Cry4 crystal structure available is that of a non-migratory bird, pigeon (Columba livia). Homology modeling is a computational process in which a 3D protein structure can be constructed by using the structure of another, similar protein, as a template. In this investigation homology models of birds' Cry4 from migratory birds (European robin and Blackcap) and non-migratory bird species (Chicken and Zebra finch) have been constructed and studied. The comparison reveals little structural and dynamical difference of various Cry4, and we try to explain why in spite of these similarities some cryptochromes of migration birds show a stronger magnetic sensing ability. With this investigation we hope to get a deeper insight into the structural differences that are important for magnetic sensing in migratory birds vs. non- migratory birds.

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