Active-site alkylation destabilizes human O6-alkylguanine DNA alkyltransferase.
O(6)-alkylguanine-DNA alkyltransferase (AGT) repairs pro-mutagenic O(6)-alkylguanine and O(4)-alkylthymine lesions in DNA. The alkylated form of the protein is not reactivated; instead, it is rapidly ubiquitinated and degraded. Here, we show that alkylation destabilizes the native fold of the protein by 0.5-1.2 kcal/mole and the DNA-binding function by 0.8-1.4 kcal/mole. On this basis, we propose that destabilization of the native conformational ensemble acts as a signal for ubiquitination.
Rasimas
Joseph J
JJ
Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA.
Dalessio
Paula A
PA
Ropson
Ira J
IJ
Pegg
Anthony E
AE
Fried
Michael G
MG
D000478:Alkylation; D001665:Binding Sites; D002942:Circular Dichroism; D004247:DNA / Q000378:metabolism*; D006801:Humans; D019853:O(6)-Methylguanine-DNA Methyltransferase / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D011994:Recombinant Proteins / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism; D014508:Urea / Q000494:pharmacology
D011994:Recombinant Proteins; D025801:Ubiquitin; D014508:Urea; D004247:DNA; D019853:O(6)-Methylguanine-DNA Methyltransferase