Central nervous system myelin is a dynamic entity arising from membrane processes extended from oligodendrocytes, which form a tightly-wrapped multilamellar structure around neurons In mature myelin, the predominant splice isoform of classic MBP is 18.5 kDa In solution. MBP is an extended, intrinsically disordered protein with a large effective protein surface for myriad interactions. and possesses transient. and/or induced ordered secondary Structure elements for molecular association or recognition Here, we show by nanopore analysis that the divalent cations copper and zinc induce a compaction of the extended protein In vitro, suggestive of a tertiary conformation that may reflect its arrangement in myelin. (c) 2009 Elsevier Inc All rights reserved