2qmt
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(New page: 200px<br /><applet load="2qmt" size="350" color="white" frame="true" align="right" spinBox="true" caption="2qmt, resolution 1.05Å" /> '''Crystal Polymorphism...)
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Revision as of 09:03, 23 January 2008
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Crystal Polymorphism of Protein GB1 Examined by Solid-state NMR and X-ray Diffraction
Overview
The study of micro- or nanocrystalline proteins by magic-angle spinning, (MAS) solid-state NMR (SSNMR) gives atomic-resolution insight into, structure in cases when single crystals cannot be obtained for diffraction, studies. Subtle differences in the local chemical environment around the, protein, including the characteristics of the cosolvent and the buffer, determine whether a protein will form single crystals. The impact of these, small changes in formulation is also evident in the SSNMR spectra;, however, the changes lead only to correspondingly subtle changes in the, spectra. Here, we demonstrate that several formulations of GB1, microcrystals yield very high quality SSNMR spectra, although only a, subset of conditions enable growth of single crystals. We have, characterized these polymorphs by X-ray powder diffraction and assigned, the SSNMR spectra. Assignments of the 13C and 15N SSNMR chemical shifts, confirm that the backbone structure is conserved, indicative of a common, protein fold, but side chain chemical shifts are changed on the surface of, the protein, in a manner dependent upon crystal packing and electrostatic, interactions with salt in the mother liquor. Our results demonstrate the, ability of SSNMR to reveal minor structural differences among crystal, polymorphs. This ability has potential practical utility for studying the, formulation chemistry of industrial and therapeutic proteins, as well as, for deriving fundamental insights into the phenomenon of single-crystal, growth.
About this Structure
2QMT is a Single protein structure of sequence from Staphylococcus aureus with , and as ligands. Full crystallographic information is available from OCA.
Reference
Crystal Polymorphism of Protein GB1 Examined by Solid-State NMR Spectroscopy and X-ray Diffraction., Schmidt HL, Sperling LJ, Gao YG, Wylie BJ, Boettcher JM, Wilson SR, Rienstra CM, J Phys Chem B. 2007 Dec 27;111(51):14362-14369. Epub 2007 Dec 4. PMID:18052145
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