XP Screens: Crystal Screening with TEW - The Protein Crystal Glue

The Anderson-Evans Polyoxotungstate [TeW₆O₂₄]^6- (TEW) is a universal and flexible crystallization additive^[1] that is integrated in our XP Screens. It was shown to improve crystal quality and resolution by:

binding to the protein surface and forming tight crystal lattice contacts^[3-7]
acting as linker in various orientations and thereby creating either smaller (PDB: 4OUA) or larger (PDB: 4PHI) protein-protein distances^[3,4]
heterogeneous crystallization of two different protein forms in one single crystal (PDB: 4OUA)^[4]
inducing new crystal forms with access to the active site (PDB: 6ZDK, 6ZDL, 6ZFA)^[5]
covalently binding and structurally adapting to fit into protein molecules (PDB: 4Z12, 4Z13)^[2]

Covalent binding of W to carboxylic oxygen atoms of glutamic acid (cgAUS1, PDB code: 4Z12, 4Z13)[2]

Figure 1: Covalent binding of Tungsten to carboxylic oxygen atoms of glutamic acid (PDB: 4Z12, 4Z13).^[2] Figure from [1].

TEW Properties

Chemical structure of TEW, Figure from [1]

Centrosymmetric, inorganic cluster
Disk-shaped ion [TeW₆O₂₄]^6-
Dimensions: 9 x 9 x 3 Å³
MW: 1.615 g/mol (ion)
Highly soluble in aqueous solutions (100 mM) and stable over a wide pH range
6 tungsten atoms provide strong anomalous scattering signal for phasing

Figure 2 (right): Chemical structure of TEW. Figure from [7].

Advantages of XP Screens

Convenient initial screening with up to 10 mM TEW
Tight crystal contacts
Improved crystal quality and resolution
New crystal forms (e.g to provide access to binding pockets)
Direct phasing

Figure taken from [1]

The XP Screen

The XP Screen is a convenient initial screen that has successfully induced protein crystallization with low TEW concentrations such as 1 mM^[5,6]. In some cases however, higher concentration of 5 or 10 mM TEW are needed.

The XP Up Screen

The XP Up Screen is an upgrade of the well-established XP Screen. It contains 96 of the most prominent screening solutions that are long-term stable in the presence of up to 10 mM TEW.

Product	Cat. No.	Description
XP Screen	CS-350	96 screening conditions with 1 mM TEW
XP Up Screen	CS-351	96 screening conditions to be upgraded with up to 10 mM TEW
Anderson-Evans polyoxotungstate (TEW)	X-TEW-5	Additive for optimization

Questions or inquiries?

E-mail Christin for technical inquiries or further information: xtals@jenabioscience.com

References

[1] Bijelic et al. (2017) Ten Good Reasons for the Use of the Tellurium-Centered Anderson-Evans Polyoxotungstate in Protein Crystallography. Acc. Chem. Res. 50:1441.
[2] Molitor et al. (2016) In situ formation of the first proteinogenically functionalized [TeW6O24O2(Glu)]7- structure reveals unprecedented chemical and geometrical features of the Anderson-type cluster. Chem. Commun. 52:12286.
[3] Bijelic et al. (2015) Hen Egg-White Lysozyme Crystallisation: Protein Stacking and Structure Stability Enhanced by a Tellurium(VI)-Centred Polyoxotungstate. ChemBioChem 16:233.
[4] Mauracher et al. (2014) Latent and active abPPO4 mushroom tyrosinase cocrystallized with hexatungstotellurate(VI) in a single crystal. Acta Cryst. D 70:2301.
[5] Sobala et al. (2020) Structure of human endo-α-1,2-mannosidase (MANEA), an antiviral host-glycosylation target. PNAS 117 (47):29595.
[6] Ames et al. (2020) Identifying a Molecular Mechanism That Imparts Species-Specific Toxicity to YoeB Toxins. Front. Microbiol. 11:959.
[7] Mac Sweeney et al. (2018) The crystallization additive hexatungstotellurate promotes the crystallization of the HSP70 nucleotide binding domain into two different crystal forms. PLOS one 13 (6): e0199639.