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Architectural DNA-binding proteins (ADBPs) are abundant constituents of eukaryotic or bacterial chromosomes that bind DNA promiscuously and function in diverse DNA reactions. They generate large conformational changes in DNA upon binding yet can slide along DNA when searching for functional binding sites. Here we investigate the mechanism by which ADBPs diffuse on DNA by single-molecule analyses of mutant proteins rationally chosen to distinguish between rotation-coupled diffusion and DNA surface sliding after transient unbinding from the groove(s). The properties of yeast Nhp6A mutant proteins, combined with molecular dynamics simulations, suggest Nhp6A switches between two binding modes: a static state, in which the HMGB domain is bound within the minor groove with the DNA highly bent, and a mobile state, where the protein is traveling along the DNA surface by means of its flexible N-terminal basic arm. The behaviors of Fis mutants, a bacterial nucleoid-associated helix-turn-helix dimer, are best explained by mobile proteins unbinding from the major groove and diffusing along the DNA surface. Nhp6A, Fis, and bacterial HU are all near exclusively associated with the chromosome, as packaged within the bacterial nucleoid, and can be modeled by three diffusion modes where HU exhibits the fastest and Fis the slowest diffusion.

Previous studies on false memory of non-semantic stimuli reported that false memories were produced for items that were unstudied but that were similar to the studied items. However, it remains unclear what representations of false memory are constructed by studied items and how the representations of studied items contribute to the occurrence of false memory. Therefore, we examined whether false memory is produced in the Deese-Roediger-McDermott (DRM) paradigm for non-semantic stimuli (i.e., facial lists), which was divided according to the morphological characteristics quantified by principal component analysis, and whether the false memory rate could be quantitatively predicted by the morphological characteristics of the studied items with a regression analysis. Thirty-five participants memorized five faces and performed a recognition memory test, including an unstudied lure item whose morphological characteristics were approximately the average of the studied items. The results showed that the lure items were more likely to be falsely remembered than other unstudied items whose morphological characteristics were not the average of the studied items, indicating that false memory of non-semantic stimuli was produced in the DRM paradigm owing to the morphological characteristics of the studied items. In contrast, the false memory rate could not be quantitatively explained by each kind of morphological characteristic. This indicates that false memory was not caused by the particular morphological characteristic of the studied items. Moreover, these results implicate that false memory of non-semantic stimuli in the DRM paradigm was provoked by gist representation of the studied items., Author(s): Daisuke Shimane [sup.1] , Hiroshi Matsui [sup.1] , Yuji Itoh [sup.1] Author Affiliations: (1) grid.26091.3c, 0000 0004 1936 9959, Department of Psychology, Keio University, , 2-15-45, Mita, Minato-Ku, 108-8345, [...]