Proteins order

Blake et al. (1983) refined the structures of human lysozyme (HL) and tortoise egg white lysozyme (TEWL) to 1.5 and 1.6 A resolution, respectively. The diffraction was modeled as arising from three components the protein, ordered water, and disordered water. Most of the water in the crystals (i.e., 60—80%) is disordered. The analysis located 143 molecules of ordered water out of about 350 per HL molecule, and 122 molecules out of 650 per TEWL molecule. The ordered water covers 75% of the available surface of the the protein. One-third (TEWL) to one-half (HL) of the total surface is unavailable for analysis of the adjacent water, owing to crystal contacts or disorder in the protein region. Thus, the estimate of surface coverage is in good agreement with the 300 molecules of water estimated by heat capacity measurements as full hydration (0.38 h). The area covered per water molecule is estimated as 18.9... 

In the PSSC procedure itself, initially the full structure of a protein of interest was subjected to search for structural similarity using the Dali (FSSP) and Combinatorial Extension (CE) algorithms. The searches were performed across the entire PDB and yielded lists of structurally similar proteins ordered by decreasing similarity (Figure 9.14). The entries which were deemed interesting... 

Section 3. Proteins The Mobile Water Phase Proteins Ordered Water Polysaccharide Interactions with Water... 

Heating Reversibly Increases Protein Order, an Inverse Temperature Transition... 

Quite the inverse occurs for water-dissolved protein of interest here that is, by the consilient mechanism, heating from below to above the folding transition increases the order of the model protein. Because heating increases protein order, the transition is called an inverse temperature transition. 

Keywords Dynamics, Solution NMR, Solid-state NMR, Globular proteins. Membrane proteins. Order parameters. Relaxation rates. Dipolar couplings. Dynamic interference... 

J.L. Lorieau, A.E. McDermott, Conformational flexibihty of a microcrystalline globular protein order parameters by sohd-state NMR spectroscopy, J. Am. Chem. Soc. 128 (2006) 11505-11512. 

FIGURE 23.23 A globular protein, ordered so as to put the nonpolar side chains in the inside of the glob and the polar side chains outside interacting with the polar solvent medium. 

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