Comparison of binding parameters of (1S)-camphor and (1R)-camphor

Parameter	(1S)-camphor	(1R)-camphor
Uncoupling (%)	11	3
For oxidized protein:	-	-
Kd (microM)	7.4	2.3
Kspin	1033	1267
P(1/2) (MPa)	288	305
deltaV (cm3/mol)	-57	-70
spin trans. rate (% low-spin/K)	0.304	0.106
rmsd (Angstrom)	0.90	0.55
For reduced protein:	-	-
deltaH (kJ/mol)	-4.4	9.5
deltaS (J/Kmol)	60.2	131.9
deltaG (kJ/mol)	-22.3	-29.9
rmsd (Angstrom)	0.97	0.58

Table 1.

-Kd was measured at 277 K in 60% glycerol.
-Kspin was measured at 297 K.
-P(1/2) and deltaV are measured by application of hydrostatic pressure.
-The spin transition rate is given for fast cooling from 298 to 78 K.
-The rmsd is the root mean standard deviation of the camphor non-hydrogen atoms from their mean positions during molecular dynamics simulations of the camphor-cytochrome P450cam complexes at 300 K.
-See [10] for details of the above.
-deltaH, deltaS and deltaG are derived from measurements of the kon and koff by FTIR of the CO stretch band at 297 K in 60% glycerol.[1]

All these measurements point to the less optimal binding and greater mobility of (1S)-camphor in the cytochrome P450cam binding site compared to (1R)-camphor.

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Wade et al. (1996) Fundamentals of Enzyme-Ligand Interactions in Cytochrome P450cam
POPE5 Conference Proceedings
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