Quantitative measurement of small through-hydrogen-bond and 'through-space' 1H-113Cd and 1H-199Hg J couplings in metal-substituted rubredoxin from Pyrococcus furiosus.
A method is described for measurement of small unresolvable heteronuclear J couplings. The method is based on quantitative analysis of a phase-purged heteronuclear spin-echo difference spectrum, and is demonstrated for measuring 1H-113Cd and 1H-199Hg J couplings in metal-substituted rubredoxin (M(r) approximately 5.4 kDa) from Pyrococcus furiosus. Couplings from cadmium to backbone amide protons that are hydrogen bonded to the Cys-S atoms directly bonded to Cd vary from smaller than 0.3 to 1.8 Hz; a 'through-space' coupling between Cd and the protons of an alanine methyl group was measured to be 0.3 Hz. Couplings to 199Hg are significantly larger and fall in the 0.4-4 Hz range.
Blake
P R
PR
Department of Chemistry and Biochemistry, University of Maryland Baltimore County 21228.
Lee
B
B
Summers
M F
MF
Adams
M W
MW
Park
J B
JB
Zhou
Z H
ZH
Bax
A
A
D000595:Amino Acid Sequence; D001105:Archaea / Q000737:chemistry*; D002104:Cadmium / Q000737:chemistry*; D006860:Hydrogen Bonding; D008628:Mercury / Q000737:chemistry*; D011487:Protein Conformation; D012416:Rubredoxins / Q000737:chemistry*
D012416:Rubredoxins; D002104:Cadmium; D008628:Mercury