Clock Proteins (IMAGE) University of California - Santa Cruz Caption Cryptochrome is one of four main clock proteins that drive daily biological rhythms. This illustration shows a "pocket" in the clock protein complex where binding of the "tail" of the cryptochrome protein helps regulate the timing of the biological clock. Credit G. Carlo Parico Usage Restrictions For use only with news coverage of this research License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.