Repair of DNA Dewar Photoproduct to (6-4) photoproduct in (6-4) Photolyase

• Dewar photoproduct (Dewar PP) is the valence isomer of (6-4) photoproduct ((6-4)PP) in photodamaged DNA. Compared to the extensive studied CPD photoproducts, the underlying repair mechanisms for the (6-4)PP, and especially for the Dewar PP, are not well-established to date. In this paper, the repair mechanism of DNA Dewar photoproduct T(dew)C in (6-4) photolyase was elucidated using hybrid density functional theory. Our results showed that, during the repair process, the T(dew)C has to isomerize to T(6-4)C photolesion first via direct C6'-N3' bond cleavage facilitated by electron injection. This isomerization mechanism is energetically much more efficient than other possible rearrangement pathways. The calculations provide a theoretical interpretation to recent experimental observations.

Ämnesord

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Nyckelord

DENSITY-FUNCTIONAL THEORY

REACTION-MECHANISM

METHYL INTERMEDIATE

ENZYMATIC-REACTIONS

CRYSTAL-STRUCTURE

ENZYMES

LIGHT

PHOTOLESIONS

HISTIDINES

MOLECULES

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