2QMT

Crystal Polymorphism of Protein GB1 Examined by Solid-state NMR and X-ray Diffraction

Summary for 2QMT

• Entry DOI: 10.2210/pdb2qmt/pdb
• Related: 1PGA 1PGB 2GB1 2GI9 2JSV
• Descriptor: Immunoglobulin G-binding protein G, PHOSPHATE ION, (4R)-2-METHYLPENTANE-2,4-DIOL, ... (5 entities in total)
• Functional Keywords: immunglobulin binding domain, thermostable, immune system
• Biological source: Staphylococcus aureus
• Cellular location: Secreted, cell wall; Peptidoglycan-anchor (Potential): P19909
• Total number of polymer chains: 1
• Total formula weight: 6562.14

Authors

Frericks Schmidt, H.L.,Sperling, L.J.,Gao, Y.G.,Wylie, B.J.,Boettcher, J.M.,Wilson, S.R.,Rienstra, C.M. (deposition date: 2007-07-16, release date: 2007-12-25, Last modification date: 2023-08-30)

Primary citation

Frericks Schmidt, H.L.,Sperling, L.J.,Gao, Y.G.,Wylie, B.J.,Boettcher, J.M.,Wilson, S.R.,Rienstra, C.M.
Crystal Polymorphism of Protein GB1 Examined by Solid-State NMR Spectroscopy and X-ray Diffraction.
J.Phys.Chem.B, 111:14362-14369, 2007

PubMed Abstract: 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.

PubMed: 18052145
DOI: 10.1021/jp075531p

Experimental method

X-RAY DIFFRACTION (1.05 Å)