Using Paramagnetism to Slow Down Nuclear Relaxation in Protein NMR

Henry W. Orton; Ilya Kuprov; Choy Theng Loh; Gottfried Otting

doi:10.1021/acs.jpclett.6b02417

Using Paramagnetism to Slow Down Nuclear Relaxation in Protein NMR

Henry W. Orton, Ilya Kuprov, Choy Theng Loh, Gottfried Otting^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

20 Citations (Scopus)

Abstract

Paramagnetic metal ions accelerate nuclear spin relaxation; this effect is widely used for distance measurement and called paramagnetic relaxation enhancement (PRE). Theoretical predictions established that, under special circumstances, it is also possible to achieve a reduction in nuclear relaxation rates (negative PRE). This situation would occur if the mechanism of nuclear relaxation in the diamagnetic state is counterbalanced by a paramagnetic relaxation mechanism caused by the metal ion. Here we report the first experimental evidence for such a cross-correlation effect. Using a uniformly ¹⁵N-labeled mutant of calbindin D_9k loaded with either Tm³⁺ or Tb³⁺, reduced R₁ and R₂ relaxation rates of backbone ¹⁵N spins were observed compared with the diamagnetic reference (the same protein loaded with Y³⁺). The effect arises from the compensation of the chemical shift anisotropy tensor by the anisotropic dipolar shielding generated by the unpaired electron spin.

Original language	English
Pages (from-to)	4815-4818
Number of pages	4
Journal	Journal of Physical Chemistry Letters
Volume	7
Issue number	23
DOIs	https://doi.org/10.1021/acs.jpclett.6b02417
Publication status	Published - 1 Dec 2016

Access to Document

10.1021/acs.jpclett.6b02417

Cite this

@article{67e924f325554a779f12d099fa6aee54,

title = "Using Paramagnetism to Slow Down Nuclear Relaxation in Protein NMR",

abstract = "Paramagnetic metal ions accelerate nuclear spin relaxation; this effect is widely used for distance measurement and called paramagnetic relaxation enhancement (PRE). Theoretical predictions established that, under special circumstances, it is also possible to achieve a reduction in nuclear relaxation rates (negative PRE). This situation would occur if the mechanism of nuclear relaxation in the diamagnetic state is counterbalanced by a paramagnetic relaxation mechanism caused by the metal ion. Here we report the first experimental evidence for such a cross-correlation effect. Using a uniformly 15N-labeled mutant of calbindin D9k loaded with either Tm3+ or Tb3+, reduced R1 and R2 relaxation rates of backbone 15N spins were observed compared with the diamagnetic reference (the same protein loaded with Y3+). The effect arises from the compensation of the chemical shift anisotropy tensor by the anisotropic dipolar shielding generated by the unpaired electron spin.",

author = "Orton, {Henry W.} and Ilya Kuprov and Loh, {Choy Theng} and Gottfried Otting",

note = "Publisher Copyright: {\textcopyright} 2016 American Chemical Society.",

year = "2016",

month = dec,

day = "1",

doi = "10.1021/acs.jpclett.6b02417",

language = "English",

volume = "7",

pages = "4815--4818",

journal = "Journal of Physical Chemistry Letters",

issn = "1948-7185",

publisher = "American Chemical Society",

number = "23",

}

TY - JOUR

T1 - Using Paramagnetism to Slow Down Nuclear Relaxation in Protein NMR

AU - Orton, Henry W.

AU - Kuprov, Ilya

AU - Loh, Choy Theng

AU - Otting, Gottfried

PY - 2016/12/1

Y1 - 2016/12/1

N2 - Paramagnetic metal ions accelerate nuclear spin relaxation; this effect is widely used for distance measurement and called paramagnetic relaxation enhancement (PRE). Theoretical predictions established that, under special circumstances, it is also possible to achieve a reduction in nuclear relaxation rates (negative PRE). This situation would occur if the mechanism of nuclear relaxation in the diamagnetic state is counterbalanced by a paramagnetic relaxation mechanism caused by the metal ion. Here we report the first experimental evidence for such a cross-correlation effect. Using a uniformly 15N-labeled mutant of calbindin D9k loaded with either Tm3+ or Tb3+, reduced R1 and R2 relaxation rates of backbone 15N spins were observed compared with the diamagnetic reference (the same protein loaded with Y3+). The effect arises from the compensation of the chemical shift anisotropy tensor by the anisotropic dipolar shielding generated by the unpaired electron spin.

AB - Paramagnetic metal ions accelerate nuclear spin relaxation; this effect is widely used for distance measurement and called paramagnetic relaxation enhancement (PRE). Theoretical predictions established that, under special circumstances, it is also possible to achieve a reduction in nuclear relaxation rates (negative PRE). This situation would occur if the mechanism of nuclear relaxation in the diamagnetic state is counterbalanced by a paramagnetic relaxation mechanism caused by the metal ion. Here we report the first experimental evidence for such a cross-correlation effect. Using a uniformly 15N-labeled mutant of calbindin D9k loaded with either Tm3+ or Tb3+, reduced R1 and R2 relaxation rates of backbone 15N spins were observed compared with the diamagnetic reference (the same protein loaded with Y3+). The effect arises from the compensation of the chemical shift anisotropy tensor by the anisotropic dipolar shielding generated by the unpaired electron spin.

UR - http://www.scopus.com/inward/record.url?scp=85000977859&partnerID=8YFLogxK

U2 - 10.1021/acs.jpclett.6b02417

DO - 10.1021/acs.jpclett.6b02417

M3 - Article

SN - 1948-7185

VL - 7

SP - 4815

EP - 4818

JO - Journal of Physical Chemistry Letters

JF - Journal of Physical Chemistry Letters

IS - 23

ER -

Using Paramagnetism to Slow Down Nuclear Relaxation in Protein NMR

Abstract

Access to Document

Other files and links

Fingerprint

Cite this