“…Osmium tetroxide probes of DNA structure have a number of advantages as compared to enzymatic and other chemical probes [4,5,16]; among these is the established chemistry of their interaction with DNA components (for review, see [18]), detection of the osmium binding sites at single nucleotide resolution [5,[19][20][21][22][23], availability of antibodies against osmiummodified DNAs [5,24], etc. Os,TMEN represents a second osmium probe which can be applied to probe DNA structure in situ.…”