Myoglobin, crystals

Figure 2.9. Schematic of a matrix-assisted laser desorption/ionization (MALDI) event. The SEM micrograph depicts sinapinic acid-equine myoglobin crystal from a sample prepared according to the dried drop sample preparation method. In the desorption event neutral matrix molecules (M), positive matrix ions (M+), negative matrix ions (M-), neutral analyte molecules (N), positive analyte ions (+), and negative analyte ions (-) are created and/or transferred to the gas phase. Reprinted from A. Westman-Brinkmalm and G. Brinkmalm (2002). In Mass Spectrometry and Hyphenated Techniques in Neuropeptide Research, J. Silberring and R. Ekman (eds.) New York John Wiley Sons, 47-105. With permission of John Wiley Sons, Inc.

Doster et al. (1986) determined the specific heat of water in myoglobin crystals from 180 to 270 K, as the difference between scanning... 

Mossbauer spectroscopic measurements suggest that the hydration water of myoglobin and the internal motions of the protein are coupled. [ Fe]Ferricyanide diffused into the solvent of myoglobin crystals exhibits (x ) values equal to those for the heme iron for temperatures below 250 K, and greater than those for the heme iron at higher temperatures (50% greater at 300 K) (Parak, 1986). The [ Fe]ferricyanide in the crystal monitors motions of the hydration water [ Fe]ferricyanide in bulk water shows no Mossbauer spectrum. 

Other measurements also suggest that the hydration water of myoglobin and the internal motions of the protein are coupled. For example, the 10 GHz dielectric response of the water of myoglobin crystals has a temperature dependence close to that of the heme iron (Singh et al., 1981). The O-D stretching band (Doster et al, 1986) is also correlated with the above properties (Fig. 26). The temperature dependence of the infrared properties and of the heat capacity (Doster et al., 1986) were interpreted as indicating that the hydration water melts at 190 K and... 

Fig. 26. Temperature dependence of various properties of myoglobin crystals , frequency of the O-D band maximum (IR) —, dielectric relaxation time of water (schematic) ---—, Lamb-Mossbauer factor,/o, after subtracting the harmonic mode (sche-...

Fig. 27. Mean square displacement averaged over all atoms of myoglobin, but corrected for the water content, determined from Rayleigh scattering of Mossbauer radiation. (Sample a) , Lyophilized sperm whale myoglobin hydrated for 3 days at 0.37 relative humidity. (Sample b) O, Hydrated at 0.94 relative humidity. (Sample c) A, 29.6 wt% solution. (Sample d) 9, Myoglobin crystals. From Krupyanskii etal. (1982).

Figure 4.51. Myoglobin Crystal and X-Ray. (A) Crystal of myoglobin. (B) X-ray precession photograph of a myoglobin crystal. [(A) Mel Pollinger/Fran Heyl Associates.]... 

Bodo, G., Dintzis, H. M., Kendrew, J. C., and Wyckoff, H. W. Crystal structure of myoglobin. V. Low-resolution three-dimensional Fourier synthesis of sperm-whale myoglobin crystals. Proc. Roy. Soc. (London) A253, 70-102 (1959). 

Cheng, X., and Schoenborn, B. P. Repulsive restraints for hydrogen bonding in least-squares refinement of protein crystals. A neutron diffraction study of myoglobin crystals. Acta Cryst. A47, 314-317 (1991). 

Fiamingo FG, Brill AS, Hampton DA, Thorldldsen R. 1989. Energy distributions at the high-spin ferric sites in myoglobin crystals. Biophys J 55(l) 67-77. 

W. Doster, A. Bachleitner, R. Dunau, M. Hiebl, E. Luscher, Thermal properties of water in myoglobin crystals and solutions at subzero temperatures, Biophys. J. 50 (1986) 213-219. 

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