Phylogenetic and Functional Classification of the Photolyase/Cryptochrome Family

The photolyase/cryptochrome (PHR/CRY) family is a large group of proteins with similar structure but very diverge functions such as DNA repair, circadian clock resetting and regulation of transcription. As a result of advances in the biochemistry of the CRY/PHR family and identification of new members, several adjustments have been made to the classification of this protein family. For example, a new class of PHRs, Class III, has been proposed. Furthermore, CRYs have been suggested to function as photosensory proteins in the primordial eye of sponge larvae. Additionally, a magnetosensory function has been attributed to certain CRYs. Recent advances in the field enabled us to propose a comprehensive classification scheme and nomenclatural system for this family. This review focuses on the computational and biochemical classifications of the PHR/CRY family. Several examples show that computational analysis can give a hinge about the function of newly discovered members before performing any biochemical study.