NCP and implications for higher order chromatin structure

Crystal packing features of NCP and implications for higher order chromatin structure 

Questions concerning the structure or existence of a 30 nm chromatin fibril seem to be beyond the scope of crystallographic analysis at this time. 

The two previously described interactions are sufficient to provide a two-dimensional or sheeted chromatin structure. The intermolecular interaction that provides the third dimensional packing of chromatin sheets is most likely the metalion interaction described previously. While it is tempting to describe this feature as a general chromatin interaction, it is absent in the histone octamer crystal interaction (PDB access number 1HQ3). Instead the contact residues (the side chains of Gin 76 and Asp 77 of 2H3 and the main chain carbonyl of Leu 22 of 2H4 

Uberbacher, E.C. and Bunick, G.J. (1986) Purification of nucleoprotein particles by elution preparative gel electrophoresis ORNL/TM-10230, Oak Ridge National Laboratory, No. DE87001853 (available from the National Technical Information Service, 5285 Port Royal Rd., Springfield, VA 22161, USA). 

DeLano, W.L. (2002) The PyMOL Molecular Graphics System. DeLano Scientific, San Carlos, CA, USA. http //www.pymol.org. 

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