Chemistry Reference
In-Depth Information
a
Pb(0)
Pb(NR
2
)
2
[Pb(NR
2
)
2
]
2
Pb(S-Cys)
3
Pb(SR)
2
(OR')
2
[H
n
B(pz)
4-n
]
2
Pb
[HB(3, 5-Me
2
pz)
3
]
2
Pb
Pb-EDTA
Pb(EDTA-N
4
)
Ca sites in proteins
PbCI
2
, PbSO
4
, Pb(NO
3
)
2
PbR
4
, PbR
3
X, PBR
2
X
2
16000
12000
8000
4000
0
-4000
δ
(
207
Pb)/ppm
b
Hg(SR)
3
, Hg(S-Cys)
3
MerR
Hg(S-Cys)
4
, Rubredoxin
Hg(S-Cys)
6
, GAL4-Zn cluster
Hg(SR)
4
Hg
2
(SR)
6
Hg(SRNH
2
)
2
Hg(SR)
2
,Hg(S-Cys)
2
Merp
Hg(N-His)
2
,(S-Cys)(S*-Met)
Blue copper proteins
Hg(NRH
2
)
4
,Hg(N-His)
3
X Carbonic anhydrase
-200
-400
-600
-800
-1000
-1200
δ
(
199
Hg) / ppm
Fig. 5 (a)
207
Pb chemical shifts of various lead model complexes and
207
Pb-substituted proteins
relative to external 1 M [Pb(NO
3
)
2
] in 99.9% D
2
OpH
*
3.3. The pz represents the pyrazolyl ring
and
S
-Cys represents a thiolate from cysteine (adapted from [
87
,
89
]). (b)
199
Hg chemical shifts of
aliphatic amine/thiol model complexes and
199
Hg-substituted proteins relative to Hg(CH
3
)
2
at
298 K. The NRH
2
represents a primary amine and SR represents a thiolate, and the coordination
environments of the Hg proteins include His imidazole nitrogen, Cys thiolate S-Cys, and Met
thioether S*-Met [
90
]
coordination geometry. For examples,
199
Hg bound blue copper proteins gave rise
to signals at ca.
706 ppm
for rusticyanin [
93
,
95
]. These blue proteins have very similar coordination
environments, e.g.,
880 ppm for azurin,
749 ppm for plastocyanin, and
two histidines and one cysteine and the fourth weakly
