Related Experiment Video
Updated: Aug 9, 2026

Characterization of Glycoproteins with the Immunoglobulin Fold by X-Ray Crystallography and Biophysical Techniques
Published on: July 5, 2018
Crystal structure of Ser-22/Ile-25 form crambin confirms solvent, side chain substate correlations
A Yamano1, N H Heo, M M Teeter
1X-ray Research Laboratory, Rigaku Corporation, 3-9-12 Matsubara, Akishima, 196 Tokyo, Japan.
Abstract:
It is not agreed that correlated positions of disordered protein side chains (substate correlations) can be deduced from diffraction data. The pure Ser-22/Ile-25 (SI form) crambin crystal structure confirms correlations deduced for the natural, mixed sequence form of crambin crystals. Physical separation of the mixed form into pure SI form and Pro-22/Leu-25 (PL form) crambin and the PL form crystal structure determination (Yamano, A., and Teeter, M. M. (1994) J. Biol. Chem. 269, 13956-13965) support the proposed (Teeter, M. M., Roe, S. M., and Heo, N. H. (1993) J. Mol. Biol. 230, 292-311) correlation model. Electron density of mixed form crambin crystals shows four possible pairs of side chain conformations for heterogeneous residue 22 and nearby Tyr-29 (2(2) = 4, two conformations for each of two side chains). One combination can be eliminated because of short van der Waals' contacts. However, only two alternates have been postulated to exist in mixed form crambin: Pro-22/Tyr-29A and Ser-22/Tyr-29B. In crystals of the PL form, Pro-22 and Tyr-29A are found to be in direct van der Waals' contact (Yamano, A., and Teeter, M. M. (1994) J. Biol. Chem. 269, 13956-13965). Comparison of the SI form structure with the mixed form electron density confirms that the fourth combination of side chains does not occur and that side chain correlations are mediated by water networks.
More Related Videos
Related Concept Videos
Protein Folding
Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
Molecular Structure and Acidity
The size effect explains the change in atomic size on acidity. When comparing the acids formed from elements that belong to the same column in the periodic table, their atomic sizes...
Recrystallization: Solid–Solution Equilibria
Chemical Shift: Internal References and Solvent Effects
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
Determination of Crystal Structures

