3srn
From Proteopedia
(New page: 200px<br /><applet load="3srn" size="450" color="white" frame="true" align="right" spinBox="true" caption="3srn, resolution 2.0Å" /> '''STRUCTURAL CHANGES TH...) |
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| - | [[Image:3srn.jpg|left|200px]]<br /><applet load="3srn" size=" | + | [[Image:3srn.jpg|left|200px]]<br /><applet load="3srn" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="3srn, resolution 2.0Å" /> | caption="3srn, resolution 2.0Å" /> | ||
'''STRUCTURAL CHANGES THAT ACCOMPANY THE REDUCED CATALYTIC EFFICIENCY OF TWO SEMISYNTHETIC RIBONUCLEASE ANALOGS'''<br /> | '''STRUCTURAL CHANGES THAT ACCOMPANY THE REDUCED CATALYTIC EFFICIENCY OF TWO SEMISYNTHETIC RIBONUCLEASE ANALOGS'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The structures of two catalytically defective semi-synthetic RNases | + | The structures of two catalytically defective semi-synthetic RNases obtained by replacing aspartic acid 121 with asparagine or alanine have been determined and refined at a resolution of 2.0 A (R = 0.186 and 0.172, respectively). When these structures are compared with the refined 1.8-A structure (R = 0.204) of the fully active aspartic acid-containing enzyme (Martin, P.D., Doscher, M.S., and Edwards, B. F. P. (1987) J. Biol. Chem. 262, 15930-15938), numerous and widespread changes, much greater in number and magnitude than the small structural variations noted previously between the semisynthetic complex and RNase A, are found to have occurred. These changes include the movement of the loop containing residues 65-72 away from the active site, a more or less generalized relocation of crystallographically bound water molecules, and a number of rearrangements in the hydrogen bonding network at the active site. Most changes are far removed from the immediate site of the modifications and are distributed essentially throughout the molecule. The details of many of these changes are unique to each analog. In the asparagine analog, a destabilization in the positioning of active site residue His-119 also appears to have occurred. |
==About this Structure== | ==About this Structure== | ||
| - | 3SRN 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 SO4 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:// | + | 3SRN 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> 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=3SRN OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Pancreatic ribonuclease]] | [[Category: Pancreatic ribonuclease]] | ||
[[Category: Protein complex]] | [[Category: Protein complex]] | ||
| - | [[Category: Demel, V | + | [[Category: Demel, V S.J.]] |
| - | [[Category: Doscher, M | + | [[Category: Doscher, M S.]] |
| - | [[Category: Edwards, B | + | [[Category: Edwards, B F.P.]] |
| - | [[Category: Martin, P | + | [[Category: Martin, P D.]] |
[[Category: SO4]] | [[Category: SO4]] | ||
[[Category: hydrolase(nucleic acid]] | [[Category: hydrolase(nucleic acid]] | ||
[[Category: rna)]] | [[Category: rna)]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 19:11:26 2008'' |
Revision as of 17:11, 21 February 2008
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STRUCTURAL CHANGES THAT ACCOMPANY THE REDUCED CATALYTIC EFFICIENCY OF TWO SEMISYNTHETIC RIBONUCLEASE ANALOGS
Overview
The structures of two catalytically defective semi-synthetic RNases obtained by replacing aspartic acid 121 with asparagine or alanine have been determined and refined at a resolution of 2.0 A (R = 0.186 and 0.172, respectively). When these structures are compared with the refined 1.8-A structure (R = 0.204) of the fully active aspartic acid-containing enzyme (Martin, P.D., Doscher, M.S., and Edwards, B. F. P. (1987) J. Biol. Chem. 262, 15930-15938), numerous and widespread changes, much greater in number and magnitude than the small structural variations noted previously between the semisynthetic complex and RNase A, are found to have occurred. These changes include the movement of the loop containing residues 65-72 away from the active site, a more or less generalized relocation of crystallographically bound water molecules, and a number of rearrangements in the hydrogen bonding network at the active site. Most changes are far removed from the immediate site of the modifications and are distributed essentially throughout the molecule. The details of many of these changes are unique to each analog. In the asparagine analog, a destabilization in the positioning of active site residue His-119 also appears to have occurred.
About this Structure
3SRN is a Protein complex structure of sequences 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
Structural changes that accompany the reduced catalytic efficiency of two semisynthetic ribonuclease analogs., deMel VS, Martin PD, Doscher MS, Edwards BF, J Biol Chem. 1992 Jan 5;267(1):247-56. PMID:1730593
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