Structural Biology of the HEAT-Like Repeat Family of DNA Glycosylases.

Shi R, Shen XX, Rokas A, Eichman BF
Bioessays. 2018 40 (11): e1800133

PMID: 30264543 · DOI:10.1002/bies.201800133

DNA glycosylases remove aberrant DNA nucleobases as the first enzymatic step of the base excision repair (BER) pathway. The alkyl-DNA glycosylases AlkC and AlkD adopt a unique structure based on α-helical HEAT repeats. Both enzymes identify and excise their substrates without a base-flipping mechanism used by other glycosylases and nucleic acid processing proteins to access nucleobases that are otherwise stacked inside the double-helix. Consequently, these glycosylases act on a variety of cationic nucleobase modifications, including bulky adducts, not previously associated with BER. The related non-enzymatic HEAT-like repeat (HLR) proteins, AlkD2, and AlkF, have unique nucleic acid binding properties that expand the functions of this relatively new protein superfamily beyond DNA repair. Here, we review the phylogeny, biochemistry, and structures of the HLR proteins, which have helped broaden our understanding of the mechanisms by which DNA glycosylases locate and excise chemically modified DNA nucleobases.

© 2018 WILEY Periodicals, Inc.

MeSH Terms (9)

Archaea Bacteria Crystallography, X-Ray DNA DNA Damage DNA Glycosylases DNA Repair Eukaryota Protein Conformation

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