545 1
J . Am. Chem. SOC.1991, 113, 5451-5453
-'E
2500
:
I
I
1
I
I I
h
-0 2000
2i CI
8 1500
2
. I
8
u e,
B 8
1000
e
Eo
. I
CI
8
3
500
. CII
f3 500
0 300
400
500
600
Wavelength (nm)
700
800
Figure 1. The absorption spectrum of the one-to-one complex between the truncated zinc finger peptide CPI-C4 and cobalt(I1) in 50 m M HEPES, 50 mM NaCl buffer, pH 7.0. This spectrum is similar to that for complexes of intact zinc finger peptides although it is slightly broader and somewhat red-shifted due to the replacement of one histidine by a coordinated water. The schematic structure shown is supported by nuclear magnetic resonance studies of the parent CPl-Zn2+ complex.' This and all other experiments were performed under an atmosphere of 95% dinitrogen/5% dihydrogen.
C4
