TY - JOUR
T1 - Solid-state NMR spin-echo investigation of the metalloproteins parvalbumin, concanavalin A, and pea and lentil lectins, substituted with cadmium-113
AU - Marchetti, Paul S.
AU - Bhattacharyya, Lokesh
AU - Ellis, Paul D.
AU - Brewer, C. Fred
N1 - Funding Information:
P.S.M. and P.D.E. acknowledge constructive discussions with Professor R. G. Bryant. Further, the authors acknowledge partial support of this work by the National Institutes of Health [GM 26295 (P.D.E.) and CA-16054 (C.F.B.)] and Core Grant P30 CA-13339 (C.F.B.) and the National Science Foundation via CHE 82-07445 for support of the RIF in NMR Spectroscopy the University of South Carolina.
PY - 1988/12
Y1 - 1988/12
N2 - Solid-state 113Cd NMR spectroscopy of static powder samples of 113Cd-substituted metalloproteins, parvalbumin, concanavalin A, and pea and lentil lectins, was carried out. Cross polarization followed by application of a train of uniformly spaced π pulses was employed to investigate the origin of residual cadmium NMR linewidths observed previously in these proteins. Fourier transformation of the resulting spin-echo train yielded spectra consisting of uniformly spaced lines having linewidths of the order of 1-2 ppm. The observed linewidths were not influenced by temperature as low as -50°C or by extent of protein hydration. Since the echo-train pulse sequence is able to eliminate inhomogeneous but not homogeneous contributions to the linewidths, there is a predominant inhomogeneous contribution to cadmium linewidths in the protein CP/MAS spectra. However, significant changes in spectral intensities were observed with change in temperature and extent of protein hydration. These intensity changes are attributed for parvalbumin and concanavalin A to changes in cross-polarization efficiency with temperature and hydration. For pea and lentil lectins, this effect is attributed to the elimination of static disorder at the pea and lentil S2 metal-ion sites due to sugar binding.
AB - Solid-state 113Cd NMR spectroscopy of static powder samples of 113Cd-substituted metalloproteins, parvalbumin, concanavalin A, and pea and lentil lectins, was carried out. Cross polarization followed by application of a train of uniformly spaced π pulses was employed to investigate the origin of residual cadmium NMR linewidths observed previously in these proteins. Fourier transformation of the resulting spin-echo train yielded spectra consisting of uniformly spaced lines having linewidths of the order of 1-2 ppm. The observed linewidths were not influenced by temperature as low as -50°C or by extent of protein hydration. Since the echo-train pulse sequence is able to eliminate inhomogeneous but not homogeneous contributions to the linewidths, there is a predominant inhomogeneous contribution to cadmium linewidths in the protein CP/MAS spectra. However, significant changes in spectral intensities were observed with change in temperature and extent of protein hydration. These intensity changes are attributed for parvalbumin and concanavalin A to changes in cross-polarization efficiency with temperature and hydration. For pea and lentil lectins, this effect is attributed to the elimination of static disorder at the pea and lentil S2 metal-ion sites due to sugar binding.
UR - http://www.scopus.com/inward/record.url?scp=0041172920&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0041172920&partnerID=8YFLogxK
U2 - 10.1016/0022-2364(88)90238-7
DO - 10.1016/0022-2364(88)90238-7
M3 - Article
AN - SCOPUS:0041172920
SN - 0022-2364
VL - 80
SP - 417
EP - 426
JO - Journal of Magnetic Resonance (1969)
JF - Journal of Magnetic Resonance (1969)
IS - 3
ER -