Functions of disordered regions in mammalian early base excision repair proteins

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• Reactive oxygen species cause DNA damage, including oxidized bases and strand breaks.
• The base excision repair (BER) pathway is essential for repairing these lesions.
• DNA glycosylases initiate BER by removing damaged bases, creating abasic sites.

Purpose of the Study:

• To review the unique structural features of human DNA glycosylases and AP endonuclease.
• To discuss the critical role of disordered segments in regulating DNA repair functions.
• To explore the teleological basis for the structural flexibility of these enzymes.

Main Methods:

• Structural analysis using experimental and modeling approaches.
• Review of recent studies on unstructured regions in DNA metabolizing proteins.
• Examination of posttranslational modifications and nuclear localization signals within disordered segments.

Main Results:

• Mammalian DNA glycosylases exhibit disordered segments absent in bacterial counterparts.
• These disordered segments are crucial for protein-protein interactions and DNA recognition.
• Disordered regions contain sites for posttranslational modifications and nuclear localization.

Conclusions:

• Disordered segments are a characteristic signature of human DNA glycosylases and AP endonuclease.
• These flexible regions play a vital role in the regulation and efficiency of the base excision repair pathway.
• The structural flexibility conferred by disordered segments is essential for enzyme function and cellular response to DNA damage.