 abstractprecise positioning of nucleosomes around regulatory sites is achieved by the action of chromatin remodelers , which use the energy of atp to slide , evict or change the composition of nucleosomes . 
 chromatin remodelers act to bind nucleosomes , disrupt histone - dna interactions and translocate the dna around the histone core to reposition nucleosomes . 
 hence , remodeling is expected to involve nucleosomal intermediates with a structural organization that is distinct from intact nucleosomes . 
 we describe the identification of a partially unwrapped nucleosome structure using methods that map histone - dna contacts genome - wide . 
 this alternative nucleosome structure is likely formed as an intermediate or by - product during nucleosome remodeling by the rsc complex . 
 identification of the loss of histone - dna contacts during chromatin remodeling by rsc in vivo has implications for the regulation of transcriptional initiation . 
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