We are requesting the acquisition of the Beckman model XL-A analytical ultracentrifuge. This instrument is a state-of-the-art ultracentrifuge built along guidelines developed by the leading research experts. Though scarcely three years old, this instrument has made an impressive impact in the field with nearly 100 references to its use in a recent bibliography. It is clear that virtually all biological researchers pursuing structure-function studies will include this method in their repertoire in the near future. No comparable instrument is manufactured elsewhere. The past near abandonment of this approach is due to several factors, but the difficulties in maintenance and use of the old model E instrument are sufficient reasons by themselves. It is true that accurate alternative methods now exist in many cases for determining molecular weights of proteins, e.g., DNA sequencing and mass spectrometry. However, analytical ultracentrifugation (AUC) excels in its versatility to accommodate a wide range of experimental conditions and different types of macromolecules. Perhaps most important is the superiority of AUC in many cases for analyzing complex associating macromolecules. Another advantage of AUC is that it is based on rigorous model equations and is a primary method unlike secondary methods that require standards and the assumption that these standards behave in the same manner as the molecule being studied. In addition, AUC can provide hydrodynamic parameters from which shapes of macromolecules can be estimated. Another important advantage of this new AUC instrument is that it is compatible with computer programs for controlling and analyzing experiments giving it an extraordinary advance in user-friendliness. Now even non-experts can analyze very complex macromolecular systems utilizing powerful calculation-intensive methods with relative ease and a modest amount of training and advisement. These programs continually being improved, are available through th e internet users groups that also allows users to access all leaders in this field. The PI (HOS) of this application has nearly 20 years of experience using the model E analytical ultracentrifuge and related methods for studying simple and complex associating systems. He has even more extensive experience in computer methods of data analysis - methods that are especially valuable in analyzing data from the new AUC instrument. The projects described in this application depend extensively on the special advantages of the requested AUC instrument. For example, the majority of the studies are concerned with macromolecular associations. It is often true that two (or more) methods can provide greater insights than either method alone. Such is the case with AUC also as illustrated in the project below on polysaccharide structures. Here the combination of intrinsic viscosity and sedimentation velocity data provide information on molecular shape that is independent of the molecular hydration. Fortunately, we have top-of-the line viscometry and other modern methods that are complementary to AUC. In summary, the projects described below are at the forefront of basic research and will be greatly enhanced by, and in some case critically dependent on, analytical ultracentrifugation. This method has remarkable versatility and the current instrument sought provides outstanding advances in technology and ease of use. Currently there is no functional AUC instrument in the State of OK. However, in ~ relatively short time we have identified an impressive array of scientists in OK (about 25) who have expressed both a keen desire and an important need for the XL-A. In addition, many others in OK will undoubtedly find the instrument extremely helpful to their research as they become familiar with its capabilities and their research develops. Because of its central value in molecular biology and polymer chemistry and its expected prevalence in future labs, it is important that our students become familiar with this instrument and method. We have vigorous research activities for both undergraduate through postgraduate students. In addition, we have recently obtained two major grants serving minorities: a Howard Hughes grant, "Undergraduate Biological Sciences Education Program," of $1,000 000. over the next 4 years, and an NSF grant, "Oklahoma State Alliance for Minority Participation in Science" for $5,000,000 over the next 5 years. Both of these grants were obtained and are administered by faculty in Biochemistry and Molecular Biology. Upon acquisition of the instrument, numerous students supported by these programs will have the opportunity to become trained in this eminent technology.
