1mm8
From Proteopedia
Crystal structure of Tn5 Transposase complexed with ME DNA
Structural highlights
Function[TN5P_ECOLX] Mediates transposition of transposon Tn5 by a 'cut and paste' mechanism. First, the monomeric transposase binds the 19 bp inverted DNA repeats flanking the transposon. Then, dimerization of the DNA-bound transposase creates a synaptic DNA complex. After nicking of the first DNA strand, excision of the transposon proceeds through a series of intermediates. The transposase then mediates the insertion of the transposon at a new site by strand transfer. The activity of the wild-type transposase is very low, and is further inhibited by dimerization with the transposase inhibitor (inh).[1] [2] [3] [4] [5] [6] [7] [8] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedIn this study, evidence of novel, important interactions between a hyperactive Tn5 transposon recognition end sequence and hyperactive Tn5 transposase (Tnp) are presented. A hyperactive Tn5 end sequence, the mosaic end (ME), was isolated previously. The ME and a wild-type end sequence, the outside end (OE), differ at only three positions, yet transposition on the ME is tenfold higher than on the OE in vivo. Also, transposition on the ME is much more efficient than transposition on the OE in vitro. Here, we show that the decreased activity observed for the OE is caused by a defect in paired ends complex (PEC) formation resulting from the orientation of the A-T base-pair at position 4 of this end. Efficient PEC formation requires an interaction between the C5-methyl group (C5-Me) on the non-transferred strand thymine base at position 4 (T4) and Tnp. PEC formation on nicked substrates is much less affected by the orientation of the A-T base-pair at position 4, indicating that the C5-Me group is important only for steps preceding nicking. A recently determined co-crystal structure of Tn5 Tnp with the ME is discussed and a model explaining possible roles for the base-pair at position 4 is explored. Evidence for "unseen" transposase--DNA contacts.,Steiniger-White M, Bhasin A, Lovell S, Rayment I, Reznikoff WS J Mol Biol. 2002 Oct 4;322(5):971-82. PMID:12367522[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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