TY  - JOUR
AU  - Firczuk, M.
AU  - Wojciechowski, Marek
AU  - Czapinska, Honorata
AU  - Bochtler, Matthias
TI  - DNA intercalation without flipping in the specific ThaI-DNA complex
JO  - Nucleic acids research
VL  - 39
IS  - 2
SN  - 0301-5610
CY  - Oxford
PB  - Oxford Univ. Press
M1  - PUBDB-2015-00257
SP  - 744 - 754
PY  - 2011
AB  - The PD-(D/E)XK type II restriction endonucleaseThaI cuts the target sequence CG/CG with bluntends. Here, we report the 1.3 Å resolution structureof the enzyme in complex with substrate DNA and asodium or calcium ion taking the place of a catalyticmagnesium ion. The structure identifies Glu54,Asp82 and Lys93 as the active site residues. Thisagrees with earlier bioinformatic predictions andimplies that the PD and (D/E)XK motifs in thesequence are incidental. DNA recognition is veryunusual: the two Met47 residues of the ThaI dimerintercalate symmetrically into the CG steps of thetarget sequence. They approach the DNA from theminor groove side and penetrate the base stackentirely. The DNA accommodates the intercalatingresidues without nucleotide flipping by a doubling ofthe CG step rise to twice its usual value, which isaccompanied by drastic unwinding. Displacementof the Met47 side chains from the base pairmidlines toward the downstream CG steps leadsto large and compensating tilts of the first andsecond CG steps. DNA intercalation by ThaI isunlike intercalation by HincII, HinP1I or proteinsthat bend or repair DNA.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000286675300037
C6  - pmid:20861000
DO  - DOI:10.1093/nar/gkq834
UR  - https://bib-pubdb1.desy.de/record/205697
ER  -