TY - JOUR

T1 - Measurement of slow (mu s-ms) time scale dynamics in protein side chains by N-15 relaxation dispersion NMR spectroscopy

T2 - Application to Asn and Gln residues in a cavity mutant of T4 lysozyme

AU - Mulder, FAA

AU - Skrynnikov, NR

AU - Hon, B

AU - Dahlquist, FW

AU - Kay, LE

PY - 2001/2/7

Y1 - 2001/2/7

N2 - A new NMR experiment is presented for the measurement of mus-ms time scale dynamics of Asn and Gin side chains in proteins. Exchange contributions to the N-15 line widths of side chain residues are determined via a relaxation dispersion experiment in which the effective nitrogen transverse relaxation rate is measured as a function of the number of refocusing pulses in constant-time, variable spacing CPMG intervals. The evolution of magnetization from scalar couplings and dipole-dipole cross-correlations, which has limited studies of exchange in multi-spin systems in the past, does not affect the extraction of accurate exchange parameters from relaxation profiles of NH2 groups obtained in the present experiment. The utility of the method is demonstrated with an application to a Leu --> Ala cavity mutant of T4 lysozyme, L99A. II is shown that many of the side chain amide groups of Asn and Gin residues in the C-terminal domain of the protein are affected by a chemical exchange process which may be important in facilitating the rapid binding of hydrophobic ligands to the cavity.

AB - A new NMR experiment is presented for the measurement of mus-ms time scale dynamics of Asn and Gin side chains in proteins. Exchange contributions to the N-15 line widths of side chain residues are determined via a relaxation dispersion experiment in which the effective nitrogen transverse relaxation rate is measured as a function of the number of refocusing pulses in constant-time, variable spacing CPMG intervals. The evolution of magnetization from scalar couplings and dipole-dipole cross-correlations, which has limited studies of exchange in multi-spin systems in the past, does not affect the extraction of accurate exchange parameters from relaxation profiles of NH2 groups obtained in the present experiment. The utility of the method is demonstrated with an application to a Leu --> Ala cavity mutant of T4 lysozyme, L99A. II is shown that many of the side chain amide groups of Asn and Gin residues in the C-terminal domain of the protein are affected by a chemical exchange process which may be important in facilitating the rapid binding of hydrophobic ligands to the cavity.

KW - HETERONUCLEAR TRANSVERSE RELAXATION

KW - COUPLED SPIN SYSTEMS

KW - CHEMICAL-EXCHANGE

KW - CROSS-CORRELATION

KW - BACKBONE DYNAMICS

KW - DOMAIN

KW - RESONANCE

KW - MOTIONS

KW - SPECTRA

KW - MICROSECOND

U2 - 10.1021/ja003447g

DO - 10.1021/ja003447g

M3 - статья

VL - 123

SP - 967

EP - 975

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 5

ER -