1u1b
From Proteopedia
(New page: 200px<br /><applet load="1u1b" size="450" color="white" frame="true" align="right" spinBox="true" caption="1u1b, resolution 2.00Å" /> '''Structure of bovine ...) |
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| - | [[Image:1u1b.gif|left|200px]]<br /><applet load="1u1b" size=" | + | [[Image:1u1b.gif|left|200px]]<br /><applet load="1u1b" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1u1b, resolution 2.00Å" /> | caption="1u1b, resolution 2.00Å" /> | ||
'''Structure of bovine pancreatic Ribonuclease A in complex with 3'-phosphothymidine (3'-5')-pyrophosphate adenosine 3'-phosphate'''<br /> | '''Structure of bovine pancreatic Ribonuclease A in complex with 3'-phosphothymidine (3'-5')-pyrophosphate adenosine 3'-phosphate'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Solution NMR spin-relaxation experiments were used to compare mus-ms | + | Solution NMR spin-relaxation experiments were used to compare mus-ms dynamics in RNase A in the apo form and as complexed to the substrate-mimic, pTppAp. The crystal structure of the RNase A/pTppAp complex was determined and demonstrates that this ligand binds at the active site and utilizes established substrate binding sites in its interaction with RNase A. Relaxation-compensated CPMG experiments identify flexible residues in and around the active site in both the apo and pTppAp-bound enzyme. Quantitative analysis of the NMR spin-relaxation dispersion curves show that the time scale of motion in RNase A is unchanged when pTppAp binds and is similar to the time scale for the rate-determining step of the catalytic reaction. Temperature-dependent measurements provide an activation barrier for motion of 5.2 +/- 1.0 kcal/mol and 4.5 +/- 1.2 kcal/mol for the apo and pTppAp forms of RNase A, respectively. These data indicate very similar motion exists in the free and bound enzyme. Additionally, chemical shift data suggests that the magnitude of motion is also similar for these two forms and that it is likely that apo enzyme interconverts to a structure that resembles a ligand-bound form. Likewise, it appears that the bound conformation samples the apo enzyme form even when ligand is present. Taken together the data imply that RNase A is in a preexisting dynamic equilibrium between two conformations that represent the open and closed enzyme forms. These data suggest that ligand binding stabilizes the bound conformer but does not induce it. |
==About this Structure== | ==About this Structure== | ||
| - | 1U1B is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bos_taurus Bos taurus] with PAX as [http://en.wikipedia.org/wiki/ligand ligand]. 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:// | + | 1U1B is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bos_taurus Bos taurus] with <scene name='pdbligand=PAX:'>PAX</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. 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=1U1B OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Beach, H.]] | [[Category: Beach, H.]] | ||
[[Category: Cole, R.]] | [[Category: Cole, R.]] | ||
| - | [[Category: Gill, M | + | [[Category: Gill, M L.]] |
| - | [[Category: Loria, J | + | [[Category: Loria, J P.]] |
[[Category: PAX]] | [[Category: PAX]] | ||
[[Category: endonuclease]] | [[Category: endonuclease]] | ||
| Line 24: | Line 24: | ||
[[Category: ribonuclease]] | [[Category: ribonuclease]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:19:33 2008'' |
Revision as of 13:19, 21 February 2008
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Structure of bovine pancreatic Ribonuclease A in complex with 3'-phosphothymidine (3'-5')-pyrophosphate adenosine 3'-phosphate
Overview
Solution NMR spin-relaxation experiments were used to compare mus-ms dynamics in RNase A in the apo form and as complexed to the substrate-mimic, pTppAp. The crystal structure of the RNase A/pTppAp complex was determined and demonstrates that this ligand binds at the active site and utilizes established substrate binding sites in its interaction with RNase A. Relaxation-compensated CPMG experiments identify flexible residues in and around the active site in both the apo and pTppAp-bound enzyme. Quantitative analysis of the NMR spin-relaxation dispersion curves show that the time scale of motion in RNase A is unchanged when pTppAp binds and is similar to the time scale for the rate-determining step of the catalytic reaction. Temperature-dependent measurements provide an activation barrier for motion of 5.2 +/- 1.0 kcal/mol and 4.5 +/- 1.2 kcal/mol for the apo and pTppAp forms of RNase A, respectively. These data indicate very similar motion exists in the free and bound enzyme. Additionally, chemical shift data suggests that the magnitude of motion is also similar for these two forms and that it is likely that apo enzyme interconverts to a structure that resembles a ligand-bound form. Likewise, it appears that the bound conformation samples the apo enzyme form even when ligand is present. Taken together the data imply that RNase A is in a preexisting dynamic equilibrium between two conformations that represent the open and closed enzyme forms. These data suggest that ligand binding stabilizes the bound conformer but does not induce it.
About this Structure
1U1B is a Single protein structure of sequence from Bos taurus with as ligand. Active as Pancreatic ribonuclease, with EC number 3.1.27.5 Full crystallographic information is available from OCA.
Reference
Conservation of mus-ms enzyme motions in the apo- and substrate-mimicked state., Beach H, Cole R, Gill ML, Loria JP, J Am Chem Soc. 2005 Jun 29;127(25):9167-76. PMID:15969595
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