Supplementary Material
A Decadentate Gd(III)-Coordinating Paramagnetic Cosolvent for Protein
Relaxation Enhancement Measurement
Xin-Hua Gu1,3 • Zhou Gong1,3 • Da-Chuan Guo1 • Wei-Ping Zhang2,* • Chun Tang1,*
1
State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics and Wuhan Institute of
Physics and Mathematics, Chinese Academy of Sciences, Wuhan, Hubei Province 430071, China;
2
Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou, Zhejiang
Province, China;
3
X. Gu and Z Gong contributed equally.
* e-mail: weiping601@zju.edu.cn (W.-P. Zhang) or tanglab@wipm.ac.cn (C.Tang)
Fig. S1 Water transferred PRE using Gd(III)-DTPA-BMA as paramagnetic cosolvent observed for
maltose-binding protein (MBP, bound with β-cyclodextrin; PDB accession code 1DMB). The data were
extracted from reference (Madl et al. 2009). The residues that experience PRE values much larger than predicted
values include 5, 18, 42, 45, 53-54, 92, 101, 124, 128, 143, 174-175, 207, 246, 252-253, 272, 327, 352-356 and
370, with their amide protons shown as red spheres. The two perspectives are related by an 180º rotation.
Fig. S2 sPRE measured for protein GB1 using Gd(III)-DTPA-BMA cosolvent. Observed PRE values are shown
as red spheres; calculated sPRE values, based on PDB structure 2GB1, are shown as a black line. Error bar
stands for 1 standard deviation. Residues broadened out beyond detection are denoted as asterisks. Inset, amide
protons of residues with large PRE discrepancies indicated on the protein structure: orange balls, larger observed
sPRE values than calculated; red balls, residues that disappeared upon adding paramagnetic cosolvent.
Fig. S3 Structure models for Gd(III)-DTPA-BMA and Gd(III)-TTHA-TMA. Gd(III)-TTHA-TMA appears
more like a sphere than Gd(III)-DTPA-BMA does. Approximately, the radii for Gd(III)-DTPA-BMA and
Gd(III)-TTHA-TMA are 3.5Å and 4.0Å, respectively. The starting structures for the two models are based on
references (Ehnebom and Pedersen 1992; Burdinski et al. 2009).
Fig. S4. sPRE values for protein GB1 with addition of two different concentrations of Gd(III)-TTHA-TMA.
Asterisks denote residues that are too broad to be properly resolved. Lines connect the residues simply
for guiding the eyes. Error bars denote 1 standard deviation.
Fig. S5. Comparison between the crystal and NMR structures available for protein GB1. In the crystal structure
(1PGB), the carboxylate group of Asp22 forms a hydrogen bond with the hydroxyl group of Thr25, and side
chain of Asp22 sits on the top of the amide groups of Ala23 and Ala24. In the NMR structure (2GB1), the
hydrogen bond is likely absent, as the side chain of Asp22 swings away. Thus, the amide groups of Ala23 and
Ala24 are more exposed.
Fig. S6 sPRE measurement for MBP bound with maltotriose, upon addition of 5mM Gd(III)-TTHA-TMA
paramagnetic cosovlent. No residues are broadened out beyond detection or experiencing PREs larger than 70s -1.
The error bars denote 1 standard deviation. Lines are simply used to guide the eyes.
References
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