TY - JOUR
T1 - Supramolecular Approach to Electron Paramagnetic Resonance Distance Measurement of Spin-Labeled Proteins
AU - Yang, Zhimin
AU - Stein, Richard A.
AU - Ngendahimana, Thacien
AU - Pink, Maren
AU - Rajca, Suchada
AU - Jeschke, Gunnar
AU - Eaton, Sandra S.
AU - Eaton, Gareth R.
AU - McHaourab, Hassane S.
AU - Rajca, Andrzej
N1 - Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/4/23
Y1 - 2020/4/23
N2 - We demonstrate a host-guest molecular recognition approach to advance double electron-electron resonance (DEER) distance measurements of spin-labeled proteins. We synthesized an iodoacetamide derivative of 2,6-diazaadamantane nitroxide (DZD) spin label that could be doubly incorporated into T4 Lysozyme (T4L) by site-directed spin labeling with efficiency up to 50% per cysteine. The rigidity of the fused ring structure and absence of mobile methyl groups increase the spin echo dephasing time (Tm) at temperatures above 80 K. This enables DEER measurements of distances >4 nm in DZD-labeled T4L in glycerol/water at temperatures up to 150 K with increased sensitivity compared to that of a common spin label such as MTSL. Addition of β-cyclodextrin reduces the rotational correlation time of the label, slightly increases Tm, and most importantly, narrows (and slightly lengthens) the interspin distance distributions. The distance distributions are in good agreement with simulated distance distributions obtained by rotamer libraries. These results provide a foundation for developing supramolecular recognition to facilitate long-distance DEER measurements at near physiological temperatures.
AB - We demonstrate a host-guest molecular recognition approach to advance double electron-electron resonance (DEER) distance measurements of spin-labeled proteins. We synthesized an iodoacetamide derivative of 2,6-diazaadamantane nitroxide (DZD) spin label that could be doubly incorporated into T4 Lysozyme (T4L) by site-directed spin labeling with efficiency up to 50% per cysteine. The rigidity of the fused ring structure and absence of mobile methyl groups increase the spin echo dephasing time (Tm) at temperatures above 80 K. This enables DEER measurements of distances >4 nm in DZD-labeled T4L in glycerol/water at temperatures up to 150 K with increased sensitivity compared to that of a common spin label such as MTSL. Addition of β-cyclodextrin reduces the rotational correlation time of the label, slightly increases Tm, and most importantly, narrows (and slightly lengthens) the interspin distance distributions. The distance distributions are in good agreement with simulated distance distributions obtained by rotamer libraries. These results provide a foundation for developing supramolecular recognition to facilitate long-distance DEER measurements at near physiological temperatures.
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U2 - 10.1021/acs.jpcb.0c00743
DO - 10.1021/acs.jpcb.0c00743
M3 - Article
C2 - 32227839
AN - SCOPUS:85084025071
SN - 1520-6106
VL - 124
SP - 3291
EP - 3299
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 16
ER -