4NGI: Previously de-ionized HEW lysozyme crystallized in 1.0 M RbCl and collected at 125K

Citation:
Abstract
The adsorption of Rb(+), Cs(+), Mn(2+), Co(2+) and Yb(3+) onto the positively charged hen egg-white lysozyme (HEWL) has been investigated by solving 13 X-ray structures of HEWL crystallized with their chlorides and by applying electrospray ionization mass spectrometry (ESI-MS) first to dissolved protein crystals and then to the protein in buffered salt solutions. The number of bound cations follows the order Cs(+) < Mn(2+) approximately Co(2+) < Yb(3+) at 293 K. HEWL binds less Rb(+) (qtot = 0.7) than Cs(+) (qtot = 3.9) at 100 K. Crystal flash-cooling drastically increases the binding of Cs(+), but poorly affects that of Yb(3+), suggesting different interactions. The addition of glycerol increases the number of bound Yb(3+) cations, but only slightly increases that of Rb(+). HEWL titrations with the same chlorides, followed by ESI-MS analysis, show that only about 10% of HEWL binds Cs(+) and about 40% binds 1-2 Yb(3+) cations, while the highest binding reaches 60-70% for protein binding 1-3 Mn(2+) or Co(2+) cations. The binding sites identified by X-ray crystallography show that the monovalent Rb(+) and Cs(+) preferentially bind to carbonyl groups, whereas the multivalent Mn(2+), Co(2+) and Yb(3+) interact with carboxylic groups. This work elucidates the basis of the effect of the Hofmeister cation series on protein solubility.
PDB ID: 4NGIDownload
MMDB ID: 120306
PDB Deposition Date: 2013/11/2
Updated in MMDB: 2017/11
Experimental Method:
x-ray diffraction
Resolution: 1.7  Å
Source Organism:
Similar Structures:
Biological Unit for 4NGI: monomeric; determined by author and by software (PISA)
Molecular Components in 4NGI
Label Count Molecule
Protein (1 molecule)
1
Lysozyme C(Gene symbol: LYZ)
Molecule annotation
Chemicals (2 molecules)
1
1
2
1
* Click molecule labels to explore molecular sequence information.

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