Role of His-16 in Turnover of T4 Pyrimidine Dimer Glycosylase

Michael G. Meador, Lavanya Rajagopalan, R. Stephen Lloyd, M. L. Dodson

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

Previously, the histidine residue at position 16 in the mature T4 pyrimidine dimer glycosylase (T4-PDG) protein has been suggested to be involved in general (non-target) DNA binding. This interpretation is likely correct, but, in and of itself, cannot account for the most dramatic phenotype of mutants at this position: their inability to restore ultraviolet light resistance to a DNA repair-deficient Escherichia coli strain. Accordingly, this residue has been mutated to serine, glutamic, aspartic acid, lysine, cysteine, and alanine. The mutant proteins were expressed, purified, and their abilities to carry out several functions of T4-PDG were assessed. The mutant proteins were able to perform most functions tested in vitro, albeit at reduced rates compared with the wild type protein. The most likely explanation for the biochemical phenotypes of the mutants is that the histidine residue is required for rapid turnover of the enzyme. This role is interpreted and discussed in the context of a reaction mechanism able to account for the complete spectrum of products generated by T4-PDG during a single turnover cycle.

Original languageEnglish (US)
Pages (from-to)3348-3353
Number of pages6
JournalJournal of Biological Chemistry
Volume279
Issue number5
DOIs
StatePublished - Jan 30 2004

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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