Probing DNA- and ATP-mediated conformational changes in the MutS family of mispair recognition proteins using deuterium exchange mass spectrometry.
We have performed deuterium exchange mass spectrometry (DXMS) to probe the conformational changes that the bacterial MutS homodimer and the homologous eukaryotic heterodimer Msh2-Msh6 undergo when binding to ATP or DNA. The DXMS data support the view that high affinity binding to mispair-containing DNA and low affinity binding to fully base-paired DNA both involve forming rings by MutS protein family dimers around the DNA; however, mispair binding protects additional regions from deuterium exchange. DXMS also reveals two distinct conformations upon binding one or two ATP molecules and that binding of two ATP molecules propagates conformational changes to other regions of the protein complexes. The regions showing major changes in deuterium exchange upon ATP binding tend to occur in regions distinct from those involved in DNA binding, suggesting that although communication occurs between DNA and nucleotide binding, sliding clamps formed by binding both ATP and mispairs could result from the simultaneous action of two independent conformational changes.
Mendillo
Marc L
ML
Department of Medicine, University of California, San Diego School of Medicine, La Jolla, California 92093-0669, USA.
Putnam
Christopher D
CD
Mo
Ashley O
AO
Jamison
Jonathan W
JW
Li
Sheng
S
Woods
Virgil L
VL
Kolodner
Richard D
RD
D000255:Adenosine Triphosphate / Q000737:chemistry* / Q000378:metabolism; D004247:DNA; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D041961:Deuterium Exchange Measurement; D004926:Escherichia coli / Q000201:enzymology; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism; D013058:Mass Spectrometry; D046912:Multiprotein Complexes / Q000737:chemistry* / Q000378:metabolism; D051719:MutS DNA Mismatch-Binding Protein / Q000737:chemistry / Q000378:metabolism; D051718:MutS Homolog 2 Protein / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D020836:Protein Structure, Quaternary
D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C094443:G-T mismatch-binding protein; D046912:Multiprotein Complexes; D000255:Adenosine Triphosphate; D004247:DNA; C497172:MSH2 protein, human; D051719:MutS DNA Mismatch-Binding Protein; D051718:MutS Homolog 2 Protein; C497175:MutS protein, E coli