LINKER HISTONE TAILS AND N-TAILS OF HISTONE H3 ARE REDUNDANT - SCANNING FORCE MICROSCOPY STUDIES OF RECONSTITUTED FIBERS

The mechanisms responsible for organizing linear arrays of nucleosomes into the three-dimensional structure of chromatin are still largely u nknown. In a companion paper (Leuba, S. H., et at. 1998. Biophys. J. 7 4:2823-2829), we study the contributions of linker histone domains and the N-terminal tail of core histone H3 to extended chromatin fiber st ructure by scanning force microscopy imaging of mildly trypsinized fib ers. Here we complement and extend these studies by scanning force mic roscopy imaging of selectively reconstituted chromatin fibers, which d iffer in subtle but distinctive ways in their histone composition. We demonstrate an absolute requirement for the globular domain of the lin ker histones and a structural redundancy of the tails of linker histon es and of histone H3 in determining conformational stability.