1jc2: Difference between revisions

Revision as of 14:20, 21 February 2008

COMPLEX OF THE C-DOMAIN OF TROPONIN C WITH RESIDUES 1-40 OF TROPONIN I

OverviewOverview

The structure of the calcium-saturated C-domain of skeletal troponin C (CTnC) in complex with a regulatory peptide comprising residues 1-40 (Rp40) of troponin I (TnI) was determined using nuclear magnetic resonance (NMR) spectroscopy. The solution structure determined by NMR is similar to the structure of the C-domain from intact TnC in complex with TnI(1)(-)(47) determined by X-ray crystallography [Vassylyev, D. G., Takeda, S., Wakatsuki, S., Maeda, K., and Maeda, Y. (1998) Proc. Natl. Acad. Sci. U.S.A. 95, 4847-4852]. Changes in the dynamic properties of CTnC.2Ca2+ induced by Rp40 binding were investigated using backbone amide (15)N NMR relaxation measurements. Analysis of NMR relaxation data allows for extraction of motional order parameters on a per residue basis, from which the contribution of changes in picosecond to nanosecond time scale motions to the conformational entropy associated with complex formation can be estimated. The results indicate that binding of Rp40 decreases backbone flexibility in CTnC, particularly at the end of the C-terminal helix. The backbone conformational entropy change (-TDeltaS) associated with binding of Rp40 to CTnC.2Ca2+ determined from (15)N relaxation data is 9.6 +/- 0.7 kcal mol(-1) at 30 degrees C. However, estimation of thermodynamic quantities using a structural approach [Lavigne, P., Bagu, J. R., Boyko, R., Willard, L., Holmes, C. F., and Sykes, B. D. (2000) Protein Sci. 9, 252-264] reveals that the change in solvation entropy upon complex formation is dominant and overcomes the thermodynamic "cost" associated with "stiffening" of the protein backbone upon Rp40 binding. Additionally, backbone amide (15)N relaxation data measured at different concentrations of CTnC.2Ca2+.Rp40 reveal that the complex dimerizes in solution. Fitting of the apparent global rotational correlation time as a function of concentration to a monomer-dimer equilibrium yields a dimerization constant of approximately 8.3 mM.

About this StructureAbout this Structure

1JC2 is a Single protein structure of sequence from Gallus gallus with as ligand. Full crystallographic information is available from OCA.

ReferenceReference

Structure, dynamics, and thermodynamics of the structural domain of troponin C in complex with the regulatory peptide 1-40 of troponin I., Mercier P, Spyracopoulos L, Sykes BD, Biochemistry. 2001 Aug 28;40(34):10063-77. PMID:11513585

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-[[Image:1jc2.jpg|left|200px]]<br /><applet load="1jc2" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1jc2.jpg|left|200px]]<br /><applet load="1jc2" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1jc2" />
 '''COMPLEX OF THE C-DOMAIN OF TROPONIN C WITH RESIDUES 1-40 OF TROPONIN I'''<br />
 ==Overview==
-The structure of the calcium-saturated C-domain of skeletal troponin C, (CTnC) in complex with a regulatory peptide comprising residues 1-40, (Rp40) of troponin I (TnI) was determined using nuclear magnetic resonance, (NMR) spectroscopy. The solution structure determined by NMR is similar to, the structure of the C-domain from intact TnC in complex with, TnI(1)(-)(47) determined by X-ray crystallography [Vassylyev, D. G., Takeda, S., Wakatsuki, S., Maeda, K., and Maeda, Y. (1998) Proc. Natl., Acad. Sci. U.S.A. 95, 4847-4852]. Changes in the dynamic properties of, CTnC.2Ca2+ induced by Rp40 binding were investigated using backbone amide, (15)N NMR relaxation measurements. Analysis of NMR relaxation data allows, for extraction of motional order parameters on a per residue basis, from, which the contribution of changes in picosecond to nanosecond time scale, motions to the conformational entropy associated with complex formation, can be estimated. The results indicate that binding of Rp40 decreases, backbone flexibility in CTnC, particularly at the end of the C-terminal, helix. The backbone conformational entropy change (-TDeltaS) associated, with binding of Rp40 to CTnC.2Ca2+ determined from (15)N relaxation data, is 9.6 +/- 0.7 kcal mol(-1) at 30 degrees C. However, estimation of, thermodynamic quantities using a structural approach [Lavigne, P., Bagu, J. R., Boyko, R., Willard, L., Holmes, C. F., and Sykes, B. D. (2000), Protein Sci. 9, 252-264] reveals that the change in solvation entropy upon, complex formation is dominant and overcomes the thermodynamic "cost", associated with "stiffening" of the protein backbone upon Rp40 binding., Additionally, backbone amide (15)N relaxation data measured at different, concentrations of CTnC.2Ca2+.Rp40 reveal that the complex dimerizes in, solution. Fitting of the apparent global rotational correlation time as a, function of concentration to a monomer-dimer equilibrium yields a, dimerization constant of approximately 8.3 mM.
+The structure of the calcium-saturated C-domain of skeletal troponin C (CTnC) in complex with a regulatory peptide comprising residues 1-40 (Rp40) of troponin I (TnI) was determined using nuclear magnetic resonance (NMR) spectroscopy. The solution structure determined by NMR is similar to the structure of the C-domain from intact TnC in complex with TnI(1)(-)(47) determined by X-ray crystallography [Vassylyev, D. G., Takeda, S., Wakatsuki, S., Maeda, K., and Maeda, Y. (1998) Proc. Natl. Acad. Sci. U.S.A. 95, 4847-4852]. Changes in the dynamic properties of CTnC.2Ca2+ induced by Rp40 binding were investigated using backbone amide (15)N NMR relaxation measurements. Analysis of NMR relaxation data allows for extraction of motional order parameters on a per residue basis, from which the contribution of changes in picosecond to nanosecond time scale motions to the conformational entropy associated with complex formation can be estimated. The results indicate that binding of Rp40 decreases backbone flexibility in CTnC, particularly at the end of the C-terminal helix. The backbone conformational entropy change (-TDeltaS) associated with binding of Rp40 to CTnC.2Ca2+ determined from (15)N relaxation data is 9.6 +/- 0.7 kcal mol(-1) at 30 degrees C. However, estimation of thermodynamic quantities using a structural approach [Lavigne, P., Bagu, J. R., Boyko, R., Willard, L., Holmes, C. F., and Sykes, B. D. (2000) Protein Sci. 9, 252-264] reveals that the change in solvation entropy upon complex formation is dominant and overcomes the thermodynamic "cost" associated with "stiffening" of the protein backbone upon Rp40 binding. Additionally, backbone amide (15)N relaxation data measured at different concentrations of CTnC.2Ca2+.Rp40 reveal that the complex dimerizes in solution. Fitting of the apparent global rotational correlation time as a function of concentration to a monomer-dimer equilibrium yields a dimerization constant of approximately 8.3 mM.
 ==About this Structure==
-JC2 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus] with CA as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1JC2 OCA].
+JC2 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus] with <scene name='pdbligand=CA:'>CA</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JC2 OCA].
 ==Reference==
@@ Line 15: / Line 15: @@
 [[Category: Mercier, P.]]
 [[Category: Spyracopoulos, L.]]
-[[Category: Sykes, B.D.]]
+[[Category: Sykes, B D.]]
 [[Category: CA]]
 [[Category: ca2+ binding protein]]
@@ Line 22: / Line 22: @@
 [[Category: troponin i]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 18:06:01 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:20:56 2008''