TY - JOUR
T1 - Clostridioides difficile specific DNA adenine methyltransferase CamA squeezes and flips adenine out of DNA helix
AU - Zhou, Jujun
AU - Horton, John R.
AU - Blumenthal, Robert M.
AU - Zhang, Xing
AU - Cheng, Xiaodong
N1 - Funding Information:
We thank Dr. Clayton Woodcock for his initial involvement in CamA activity studies. We thank Ms. Yu Cao for technical assistance. The work was supported by U.S. National Institutes of Health grant R35GM134744 and Cancer Prevention and Research Institute of Texas grant RR160029. X.C. is a CPRIT Scholar in Cancer Research.
Publisher Copyright:
© 2021, The Author(s).
PY - 2021/12/1
Y1 - 2021/12/1
N2 - 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.
AB - 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.
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U2 - 10.1038/s41467-021-23693-w
DO - 10.1038/s41467-021-23693-w
M3 - Article
C2 - 34103525
AN - SCOPUS:85107522436
SN - 2041-1723
VL - 12
JO - Nature communications
JF - Nature communications
IS - 1
M1 - 3436
ER -