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PDBsum entry 4bec
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References listed in PDB file
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Key reference
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Title
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Functional coupling of duplex translocation to DNA cleavage in a type i restriction enzyme.
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Authors
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E.Csefalvay,
M.Lapkouski,
A.Guzanova,
L.Csefalvay,
T.Baikova,
I.Shevelev,
V.Bialevich,
K.Shamayeva,
P.Janscak,
I.Kuta smatanova,
S.Panjikar,
J.Carey,
M.Weiserova,
R.Ettrich.
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Ref.
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Plos One, 2015,
10,
e0128700.
[DOI no: ]
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PubMed id
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Abstract
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Type I restriction-modification enzymes are multifunctional heteromeric
complexes with DNA cleavage and ATP-dependent DNA translocation activities
located on motor subunit HsdR. Functional coupling of DNA cleavage and
translocation is a hallmark of the Type I restriction systems that is consistent
with their proposed role in horizontal gene transfer. DNA cleavage occurs at
nonspecific sites distant from the cognate recognition sequence, apparently
triggered by stalled translocation. The X-ray crystal structure of the complete
HsdR subunit from E. coli plasmid R124 suggested that the triggering mechanism
involves interdomain contacts mediated by ATP. In the present work, in vivo and
in vitro activity assays and crystal structures of three mutants of EcoR124I
HsdR designed to probe this mechanism are reported. The results indicate that
interdomain engagement via ATP is indeed responsible for signal transmission
between the endonuclease and helicase domains of the motor subunit. A previously
identified sequence motif that is shared by the RecB nucleases and some Type I
endonucleases is implicated in signaling.
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