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The dipole moments of small protein molecules were determined experimentally in order to validate the calculated dipole moments by previous investigators. We found that the agreements are satisfactory for some proteins. There are, however, many proteins for which the agreement is less than satisfactory. In order to find the cause of the disagreement, the dipole moments of these proteins were recalculated using the Brookhaven Protein Data Bank. We calculated the dipole moment due to fixed surface charges and the bond moments of all the carbonyl groups in main chain and side chains. The calculation consists of the mean moments and their mean square fluctuations. In addition, we investigated the effect of electrostatic interactions between charged sites for several proteins. These results show that incorporation of the interactions does not affect substantially the calculated dipole moments. The rms fluctuation of the dipole moment is found to be small but not negligible. In conclusion, recalculated dipole moments are in good agreement with the observed values.

In proton-donor solvents, the formation of hydrogenbonded complexes is consistently interpreted in terms of a perpendicular orientation (cp = SO-l0O0) of the two pyridine rings. For the iron complex [FeIT(C~~N&I8>,]-Clz the cis-planar conformation of the pyridyl groups has been found perfectly in line with the measured values of the chemical shifts: From the latter data a metal-nitrogen distance of 2 A. has been derived.Finally, we want to point out that, although only static molecular models have been used in the calculations, the dihedral angles proposed must be interpreted as averaged positions of equilibrium over all the possible vibrational and torsional states present in the molecule. Several secondary effects (reaction field effect,22 electric field effect due to the presence of positive charges on the nitrogens in the cations, etc.) have not been taken into account; it is very likely, however, that their contributions to the chemical shifts are small and do not invalidate the internally consistent interpretation of the results presented in this paper.Acknowledgments. We are profoundly indebted to Dr. A. A. Bothner-By for many helpful and constructive suggestions given to us during the course of the present work as well as for reading this manuscript.The dielectric constants of crystalline powders of glycine, tyrosine, glycylglycine, and ovalbumin were measured in the frequency range of 20 C.P.S. to 200 kc.p.s. It was found that dry crystals did not have an appreciable dielectric constant but that adsorbed water increased the dielectric constant markedly. The static dielectric constants, their dispersions, and the dielectric losses were measured with varied amounts of adsorbed water. The increase of the dielectric constant is proportional to the increase of water of adsorption until the first water layer is completed. The second and third layers are formed if the vapor pressure is increased. The dielectric constant, however, does not increase any more and practically levels off. The formation of multilayers does not seem to affect the dielectric constant of crystals. Apparently, only the first layer of water of adsorption makes the major contribution to the dielectric constant of wet crystals.

The dielectric constant and conductivity of calf thymus DNA were investigated at frequencies between 0.1 MHz and 70 GHz. This work is to investigate the dielectric properties of DNA in low gigahertz region and also to study whether the dielectric behavior of the water is affected by the presence of highly charged DNA. The results of these measurements indicate the presence of two anomalous dispersions, the one between 1 MHz and 1 GHz and the second one above 1 GHZ. The dispersion at low frequencies is likely to arise from polar groups in the DNA molecule. The relaxation behavior of unbound water in DNA solution is only slightly affected by the presence of DNA at concentrations below 1%.

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