Clostridioides difficile specific DNA adenine methyltransferase CamA squeezes and flips adenine out of DNA helix

Jujun Zhou, John R. Horton, Robert M. Blumenthal, Xing Zhang, Xiaodong Cheng

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Clostridioides difficile infections are an urgent medical problem. The newly discovered C.difficileadenine methyltransferase A (CamA) is specified by all C. difficile genomes sequenced to date (>300), but is rare among other bacteria. CamA is an orphan methyltransferase, unassociated with a restriction endonuclease. CamA-mediated methylation at CAAAAA is required for normal sporulation, biofilm formation, and intestinal colonization by C. difficile. We characterized CamA kinetic parameters, and determined its structure bound to DNA containing the recognition sequence. CamA contains an N-terminal domain for catalyzing methyl transfer, and a C-terminal DNA recognition domain. Major and minor groove DNA contacts in the recognition site involve base-specific hydrogen bonds, van der Waals contacts and the Watson-Crick pairing of a rearranged A:T base pair. These provide sufficient sequence discrimination to ensure high specificity. Finally, the surprisingly weak binding of the methyl donor S-adenosyl-l-methionine (SAM) might provide avenues for inhibiting CamA activity using SAM analogs.

Original languageEnglish (US)
Article number3436
JournalNature communications
Volume12
Issue number1
DOIs
StatePublished - Dec 1 2021

ASJC Scopus subject areas

  • General Chemistry
  • General Biochemistry, Genetics and Molecular Biology
  • General Physics and Astronomy

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