RESUMO
A full investigation of the possible homonuclear double-quantum recoupling sequences, based on the RN family of sequences with N < or = 20, is given. Several new RN sequences, R16(6)(5), R18(8)(5), and R18(10)(5), were applied at high magic-angle spinning rates and compared with theory. The R18(10)(5) technique can be used to recouple dipolar couplings at spinning rates up to 39 kHz, and the application of the sequence in an INADEQUATE experiment is shown for a spinning rate of 30 kHz.
Assuntos
Alanina/química , Espectroscopia de Ressonância de Spin Eletrônica , Glicina/química , Matemática , Modelos QuímicosRESUMO
A structural and thermodynamic characterization of 5F-Trp-substituted immunoglobulin binding domain B1 of streptococcal protein G (GB1) was carried out by nuclear magnetic resonance and circular dichroism spectroscopy. A single fluorine reporter atom was positioned at the center of the three-dimensional structure, uniquely poised to be exploited for studying interior properties of this protein. We demonstrate that the introduction of 5F-Trp does not affect the global and local architecture of GB1 and has no influence on the thermodynamic stability. The favorable properties of the fluorinated GB1 render this molecule a desirable model system for the development of spectroscopic methodology and theoretical calculations.
