Interdomain interaction in the motor subunit of the type I
restriction-modification system EcoR124I and their functional relevance
Sinha D1,2, Bialevich V1,2, Shamayeva K1,2, Guzanova A3,
Csefalvay E1, Reha D1, Weiserova M3, Ettrich R1,2
1Institute of
Nanobiology and Structural Biology, Global Change Research Center, Academy of
Sciences of the Czech Republic, Zamek 136, CZ-373 33 Nove Hrady, Czech Republic
2Faculty of Sciences,
University of South Bohemia in Ceske Budejovice, Zamek 136, CZ-373 33 Nove
Hrady, Czech Republic
3Institute of
Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, 14220
Praha 4, Czech Republic
EcoR124I is a type I restriction-modification (R-M) enzyme
and as such forms multifunctional heteromeric complexes with DNA cleavage and
ATP-dependent DNA translocation activities located on motor subunit HsdR. When
unmethylated invading DNA is recognized by the complex, two HsdR
endonuclease/motor subunits start to translocate dsDNA without strand
separation activity up to thousands base pairs towards the stationary enzyme
while consuming ~1 molecule of ATP per base pair advanced. Finally, after
translocation is blocked the HsdR subunits cleave the dsDNA nonspecifically far
from recognition site. The crystal structure of the motor subunit R determined
by our group in 2009 [1] revealed the four domains within the subunit in a
square planer arrangement. Computational modeling including molecular dynamics
in combination with crystallography, point mutations, in vivo and in vitro
assays reveal how interactions between these four domains contribute to
ATP-dependent DNA translocation, DNA cleavage or interdomain communication
between the translocase and endonuclease activities [2,3,4,5].
1. Mikalai
Lapkouski, et al.[2009]Structure of the motor subunit of type I
restriction-modification complex EcoR124I.,Nat Struct Mol Biol16:1.94-95Jan
2. D Sinha,
et al.[2014]Interdomain communication in the endonuclease/motor subunit of Type
I restriction-modification enzyme EcoR124I,Journal of Molecular Modeling20
(7):2334
3. Eva Csefalvay, et al.[2015]Functional coupling
of duplex translocation to DNA cleavage in a type I restriction enzyme PLOS One
accepted with minor revisions 21.1.2015.
4. Bialevich V, et al.The role
of motif III and its extended region in positioning the two helicase domains in
the motor subunit of the restriction-modification system EcoR124I [manuscript
in preparation]
5. Sinha D, et al.The helical
domain of the motor subunit of EcoR124I participates in ATPase activity and
dsDNA translocation[manuscript in preparation]