We used the AFM as the primary imaging tool and have seen the complex form very clearly. We used both 100bp and 350bp long DNA in forming the complexes and they clearly form independently of the DNA length. It is interesting that the primary product in these constructs is that two DNA molecules bind to a protein tetramer and these complexes go on to aggregate by (non-specific?) binding of the protein oligomers, forming spider-like structures. We are in the process of examining the effect of EDTA on this secondary aggregation and to try even shorter DNA to form complexes. These should be easier to analyze.
