Nitroxide side-chain dynamics in a spin-labeled helix-forming peptide revealed by high-frequency (139.5-GHz) EPR spectroscopy

被引：16

作者：

Bennati, M

Gerfen, GJ

Martinez, GV

Griffin, RG

Singel, DJ

Millhauser, GL ^{[1
]}

机构：

[1] Univ Calif Santa Cruz, Dept Chem & Biochem, Santa Cruz, CA 95064 USA

[2] MIT, Francis Bitter Natl Magnet Lab, Cambridge, MA 02139 USA

[3] MIT, Dept Chem, Cambridge, MA 02139 USA

[4] Montana State Univ, Dept Chem & Biochem, Bozeman, MT 59717 USA

[5] Yeshiva Univ Albert Einstein Coll Med, Dept Physiol & Biophys, Bronx, NY 10461 USA

来源：

JOURNAL OF MAGNETIC RESONANCE | 1999年 / 139卷 / 02期

关键词：

EPR; peptide; high frequency; side-chain dynamics; anisotropic motion;

D O I：

10.1006/jmre.1999.1769

中图分类号：

Q5 [生物化学];

学科分类号：

071010 ; 081704 ;

摘要：

High-frequency electron paramagnetic resonance (EPR) spectroscopy has been performed on a nitroxide spin-labeled peptide in fluid aqueous solution. The peptide, which follows the single letter sequence Ac-(AAAAK)(2)CAAAKA-NH2 3K-11, was reacted with the methanethiosulfonate spin label at the cysteine sulfur, The spin sensitivity of high-frequency EPR is excellent with less than 20 pmol of sample required to obtain spectra with good signal-to-noise ratios, Simulation of the temperature-dependent spectral lineshapes reveals the existence of local anisotropic motion about the nitroxide N-O bond with a motional anisotropy tau(perpendicular to)/tau(parallel to) (equivalent to N) approaching 2.6 at 306 K, Comparison with previous work on rigidly labeled peptides suggests that the spin label is reorienting about its side-chain tether, This study demonstrates the feasibility of performing 140-GHz EPR on biological samples in fluid aqueous solution. (C) 1999 Academic Press.

引用

页码：281 / 286

页数：6