CONFORMATION ZONING OF LARGE MOLECULES USING THE ANALYTICAL ULTRACENTRIFUGE

A substantial proportion of large molecules made naturally or by artif icial means exist as linear chains. In biology this includes DNA, mRNA , many important classes of sugar polymers( polysaccharides) and denat ured proteins. In physical science this includes polyethylene, polyvin ylchloride and many important polymers used in plastics and also the m any new ones being explored for use in drug delivery. Crucial to how m any of these large molecules function is their conformation in solutio n (either aqueous or organic), a realm unfortunately outside the grasp of high-resolution techniques such as X-ray crystallography. We have now however devised a quick and accessible method for identifying the conformation type or ''Zone'' of a molecule: Zone A (extra rigid rod t ype); Zone B (rigid rod type); Zone C (semi-flexible type), Zone D (co mpletely random coil) and Zone E (compact or highly branched particle) . To perform this ''Conformation Zoning'' requires a few milligrams of material and access to one of the new types of high-speed Centrifuge which are now proliferating in academic and industrial establishments. (C) 1997 Elsevier Science B.V.