Dynamic Nuclear Polarization of Sedimented Solutes

详细信息    查看全文

• 作者：Enrico Ravera ; Bj枚rn Corzilius ; Vladimir K. Michaelis ; Camilla Rosa ; Robert G. Griffin ; Claudio Luchinat ; Ivano Bertini
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：February 6, 2013
• 年：2013
• 卷：135
• 期：5
• 页码：1641-1644
• 全文大小：254K
• 年卷期：v.135,no.5(February 6, 2013)
• ISSN：1520-5126

文摘

Using the 480 kDa iron-storage protein complex, apoferritin (ApoF), as an example, we demonstrate that sizable dynamic nuclear polarization (DNP) enhancements can be obtained on sedimented protein samples. In sedimented solute DNP (SedDNP), the biradical polarizing agent is co-sedimented with the protein, but in the absence of a glass-forming agent. We observe DNP enhancement factors 蔚 > 40 at a magnetic field of 5 T and temperatures below 90 K, indicating that the protein sediment state is 鈥済lassy鈥?and suitable to disperse the biradical polarizing agent upon freezing. In contrast, frozen aqueous solutions of ApoF yield 蔚 鈮?2. Results of SedDNP are compared to those obtained from samples prepared using the traditional glass-forming agent glycerol. Collectively, these and results from previous investigations suggest that the sedimented state can be functionally described as a 鈥渕icrocrystalline glass鈥?and in addition provide a new approach for preparation of samples for DNP experiments.