FEASIBILITY TESTS FOR WIDE ANGLE FIBER DIFFRACTION STUDIES ON 14 BM-C

University Of Chicago, Chicago IL

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Abstract

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The purpose of this study is to continue to evaluate 14 BM-C for the purpose of collecting x-ray patterns from fibrous biological systems. At present, 18 ID is the only beamline at the APS that routinely offers wide-angle fiber diffraction. While many of these kinds of samples benefit from the high beam quality of doubly focussed undulator radiation, these experiments are not flux limited and a large fraction of them may well be adequately done on an appropriately configured bending magnet line. High quality wide angle fiber patterns can be taken of 14 BM-C, however, we need to continue to characterize the range of experiments that are possible at this facility (d-space range and quality of diffraction from representative test systems). If successful, 14BM-C would provide a significant increase in capacity for this kind of experiment at the APS. Furthermore, a class of biomedically important problems that can be studied by fiber diffraction is amyloidosis and prion diseases. Many of these samples are biohazardous and need to be studied under Biosafety level 2 and/or 3 conditions. We will also evaluate the setup for connective tissue studies. Type II collagen in situ in lamprey notochord will be mounted in sealed (perspex/mica) fibre sample holders. Type I collagen in situ in rat-tail tendon will be mounted in sealed (perspex/mica) fiber sample holders. Collagen short peptide crystals will be mounted in sealed capillaries. Collagenous samples may also be cryo-frozen in the same manner that single crystals are. Patterns will be compared to those taken on 18ID. All samples will studied at room temperature and are non-hazardous.