High-field 19.6T 27Al solid-state MAS NMR of in vitro aluminated brain tissue.
The combination of (27)Al high-field solid-state NMR (19.6T) with rapid spinning speeds (17.8 kHz) is used to acquire (27)Al NMR spectra of total RNA human brain temporal lobe tissues exposed to 0.10 mM Al(3+) (as AlCl(3)) and of human retinal pigment epithelial cells (ARPE-19), grown in 0.10 mM AlCl(3). The spectra of these model systems show multiple Al(3+) binding sites, good signal/noise ratios and apparent chemical shift dispersions. A single broad peak (-3 to 11 ppm) is seen for the aluminated ARPE-19 cells, consistent with reported solution-state NMR chemical shifts of Al-transferrin. The aluminated brain tissue has a considerably different (27)Al MAS NMR spectrum. In addition to the transferrin-type resonance, additional peaks are seen. Tentative assignments include: -9 to -3 ppm, octahedral AlO(6) (phosphate and water); 9 ppm, condensed AlO(6) units (Al-O-Al bridges); 24 ppm, tetrahedral AlO(3)N and/or octahedral Al-carbonate; and 35 ppm, more N-substituted aluminum and /or tetrahedral AlO(4). Thus, brain tissue is susceptible to a broad range of coordination by aluminum. Furthermore, the moderate (27)Al C(Q) values (all less than 10 MHz) suggest future NMR studies may be performed at 9.4T and a spin rate of 20 kHz.
Bryant
Pamela L
PL
Department of Physical Sciences, Howard Payne University, Brownwood, TX 76801-2794, USA. pbryant@hputx.edu
Lukiw
Walter J
WJ
Gan
Zhehong
Z
Hall
Randall W
RW
Butler
Leslie G
LG
D000535:Aluminum / Q000737:chemistry*; D000544:Alzheimer Disease / Q000378:metabolism; D001923:Brain Chemistry; D002478:Cells, Cultured; D006801:Humans; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D012313:RNA / Q000378:metabolism*; D011868:Radioisotopes; D012160:Retina / Q000378:metabolism*; D013702:Temporal Lobe / Q000378:metabolism*
D011868:Radioisotopes; D012313:RNA; D000535:Aluminum