1J7Z

Osmolyte Stabilization of Ribonuclease

Summary for 1J7Z

• Entry DOI: 10.2210/pdb1j7z/pdb
• Descriptor: RIBONUCLEASE PANCREATIC, SULFATE ION, ... (4 entities in total)
• Functional Keywords: osmolyte soaking, sarcosine, trimethylamine-n-oxide, betaine, taurine, hydrolase
• Biological source: Bos taurus (cattle); More
• Cellular location: Secreted: P61823 P61823
• Total number of polymer chains: 2
• Total formula weight: 13403.00

Authors

Ratnaparkhi, G.S.,Varadarajan, R. (deposition date: 2001-05-19, release date: 2001-06-06, Last modification date: 2017-10-04)

Primary citation

Ratnaparkhi, G.S.,Varadarajan, R.
Osmolytes stabilize ribonuclease S by stabilizing its fragments S protein and S peptide to compact folding-competent states.
J.Biol.Chem., 276:28789-28798, 2001

PubMed Abstract: 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.

PubMed: 11373282
DOI: 10.1074/jbc.M101906200

Experimental method

X-RAY DIFFRACTION (2.25 Å)