View source for 1j81

[[Image:1j81.gif|left|200px]]<br /><applet load="1j81" size="350" color="white" frame="true" align="right" spinBox="true" 
caption="1j81, resolution 2.20&Aring;" />
'''Osmolyte Stabilization of RNase'''<br />

==Overview==
Osmolytes stabilize proteins to thermal and chemical denaturation. We have studied the effects of the osmolytes sarcosine, betaine, trimethylamine-N-oxide, and taurine on the structure and stability of the protein.peptide complex RNase S using x-ray crystallography and titration calorimetry, respectively. The largest degree of stabilization is achieved with 6 m sarcosine, which increases the denaturation temperatures of RNase S and S pro by 24.6 and 17.4 degrees C, respectively, at pH 5 and protects both proteins against tryptic cleavage. Four crystal structures of RNase S in the presence of different osmolytes do not offer any evidence for osmolyte binding to the folded state of the protein or any perturbation in the water structure surrounding the protein. The degree of stabilization in 6 m sarcosine increases with temperature, ranging from -0.52 kcal mol(-1) at 20 degrees C to -5.4 kcal mol(-1) at 60 degrees C. The data support the thesis that osmolytes that stabilize proteins, do so by perturbing unfolded states, which change conformation to a compact, folding competent state in the presence of osmolyte. The increased stabilization thus results from a decrease in conformational entropy of the unfolded state.

==About this Structure==
1J81 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Bos_taurus Bos taurus] with <scene name='pdbligand=SO4:'>SO4</scene> and <scene name='pdbligand=NH2:'>NH2</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Pancreatic_ribonuclease Pancreatic ribonuclease], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.27.5 3.1.27.5] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1J81 OCA]. 

==Reference==
Osmolytes stabilize ribonuclease S by stabilizing its fragments S protein and S peptide to compact folding-competent states., Ratnaparkhi GS, Varadarajan R, J Biol Chem. 2001 Aug 3;276(31):28789-98. Epub 2001 May 23. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=11373282 11373282]
[[Category: Bos taurus]]
[[Category: Pancreatic ribonuclease]]
[[Category: Protein complex]]
[[Category: Ratnaparkhi, G S.]]
[[Category: Varadarajan, R.]]
[[Category: NH2]]
[[Category: SO4]]
[[Category: betaine]]
[[Category: osmolyte soaking]]
[[Category: sarcosine]]
[[Category: taurine]]
[[Category: trimethylamine-n-oxide]]

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