View source for 1xek

[[Image:1xek.gif|left|200px]]<br />
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'''THE CRYSTAL STRUCTURES OF LYSOZYME AT VERY LOW LEVELS OF HYDRATION'''<br />

==Overview==
Earlier studies involving water-mediated transformations in lysozyme and, ribonuclease A have shown that the overall movements in the protein, molecule consequent to the reduction in the amount of surrounding water, are similar to those that occur during enzyme action, thus highlighting, the relationship among hydration, plasticity, and action of these enzymes., Monoclinic lysozyme retains its crystallinity even when the level of, hydration is reduced further below that necessary for activity (about 0.2, gram of water per gram of protein). In order to gain insights into the, role of water in the stability and the plasticity of the protein molecule, and the geometrical basis for the loss of activity that accompanies, dehydration, the crystal structures of monoclinic lysozyme with solvent, contents of 17.6%, 16.9%, and 9.4% were determined and refined. A detailed, comparison of these forms with the normally hydrated forms show that the, C-terminal segment (residues 88-129) of domain I and the main loop, (residues 65-73) in domain II exhibit large deviations in atomic positions, when the solvent content is reduced, although the three-dimensional, structure is essentially preserved. Many crucial water bridges between, different regions of the molecule are conserved in spite of differences in, detail, even when the level of hydration is reduced well below that, required for activity. The loss of activity that accompany dehydration, appears to be caused by the removal of functionally important water, molecules from the active-site region and the reduction in the size of the, substrate binding cleft.

==About this Structure==
1XEK is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus]. Active as [http://en.wikipedia.org/wiki/Lysozyme Lysozyme], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.17 3.2.1.17] Structure known Active Site: CAT. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1XEK OCA]. 

==Reference==
Role of water in plasticity, stability, and action of proteins: the crystal structures of lysozyme at very low levels of hydration., Nagendra HG, Sukumar N, Vijayan M, Proteins. 1998 Aug 1;32(2):229-40. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=9714162 9714162]
[[Category: Gallus gallus]]
[[Category: Lysozyme]]
[[Category: Single protein]]
[[Category: Nagendra, H.G.]]
[[Category: Sukumar, N.]]
[[Category: Vijayan, M.]]
[[Category: enzyme monoclinic 5% r.h. form]]
[[Category: hydrolase]]
[[Category: o-glycosyl]]

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