C P Jaroniec1, B A Tounge, J Herzfeld, R G Griffin. 1. Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Abstract
We describe a magic-angle spinning NMR experiment for selective (13)C-(15)N distance measurements in uniformly (13)C,(15)N-labeled solids, where multiple (13)C-(15)N and (13)C-(13)C interactions complicate the accurate measurement of structurally interesting, weak (13)C-(15)N dipolar couplings. The new experiment, termed FSR (frequency selective REDOR), combines the REDOR pulse sequence with a frequency selective spin-echo to recouple a single (13)C-(15)N dipolar interaction in a multiple spin system. Concurrently the remaining (13)C-(15)N dipolar couplings and all (13)C-(13)C scalar couplings to the selected (13)C are suppressed. The (13)C-(15)N coupling of interest is extracted by a least-squares fit of the experimentally observed modulation of the (13)C spin-echo intensity to the analytical expression describing the dipolar dephasing in an isolated heteronuclear spin pair under conventional REDOR. The experiment is demonstrated in three uniformly (13)C,(15)N-labeled model systems: asparagine, N-acetyl-L-Val-L-Leu and N-formyl-L-Met-L-Leu-L-Phe; in N-formyl-[U-(13)C,(15)N]L-Met-L-Leu-L-Phe we have determined a total of 16 internuclear distances in the 2.5-6 A range.
We describe a magic-angle spinning NMR experiment for selective (13)C-(15)N distance measurements in uniformly (13)C,(15)N-labeled solids, where multiple (13)C-(15)N and (13)C-(13)C interactions complicate the accurate measurement of structurally interesting, weak (13)C-(15)N dipolar couplings. The new experiment, termed FSR (frequency selective REDOR), combines the REDOR pulse sequence with a frequency selective spin-echo to recouple a single (13)C-(15)N dipolar interaction in a multiple spin system. Concurrently the remaining (13)C-(15)N dipolar couplings and all (13)C-(13)C scalar couplings to the selected (13)C are suppressed. The (13)C-(15)N coupling of interest is extracted by a least-squares fit of the experimentally observed modulation of the (13)C spin-echo intensity to the analytical expression describing the dipolar dephasing in an isolated heteronuclear spin pair under conventional REDOR. The experiment is demonstrated in three uniformly (13)C,(15)N-labeled model systems: asparagine, n class="Chemical">N-acetyl-L-Val-L-Leu and N-formyl-L-Met-L-Leu-L-Phe; in N-formyl-[U-(13)C,(15)N]L-Met-L-Leu-L-Phe we have determined a total of 16 internuclear distances in the 2.5-6 A range.
Authors: Aneta T Petkova; Yoshitaka Ishii; John J Balbach; Oleg N Antzutkin; Richard D Leapman; Frank Delaglio; Robert Tycko Journal: Proc Natl Acad Sci U S A Date: 2002-12-12 Impact factor: 11.205
Authors: Christopher P Jaroniec; Cait E MacPhee; Vikram S Bajaj; Michael T McMahon; Christopher M Dobson; Robert G Griffin Journal: Proc Natl Acad Sci U S A Date: 2004-01-08 Impact factor: 11.205
Authors: Chad M Rienstra; Lisa Tucker-Kellogg; Christopher P Jaroniec; Morten Hohwy; Bernd Reif; Michael T McMahon; Bruce Tidor; Tomas Lozano-Pérez; Robert G Griffin Journal: Proc Natl Acad Sci U S A Date: 2002-07-29 Impact factor: 11.205
Authors: Myungwoon Lee; Tuo Wang; Olga V Makhlynets; Yibing Wu; Nicholas F Polizzi; Haifan Wu; Pallavi M Gosavi; Jan Stöhr; Ivan V Korendovych; William F DeGrado; Mei Hong Journal: Proc Natl Acad Sci U S A Date: 2017-05-31 Impact factor: 11.205