1ssa: Difference between revisions
New page: left|200px<br /><applet load="1ssa" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ssa, resolution 2.0Å" /> '''A STRUCTURAL INVESTIG... |
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[[Image:1ssa.gif|left|200px]]<br /><applet load="1ssa" size=" | [[Image:1ssa.gif|left|200px]]<br /><applet load="1ssa" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1ssa, resolution 2.0Å" /> | caption="1ssa, resolution 2.0Å" /> | ||
'''A STRUCTURAL INVESTIGATION OF CATALYTICALLY MODIFIED F12OL AND F12OY SEMISYNTHETIC RIBONUCLEASES'''<br /> | '''A STRUCTURAL INVESTIGATION OF CATALYTICALLY MODIFIED F12OL AND F12OY SEMISYNTHETIC RIBONUCLEASES'''<br /> | ||
==Overview== | ==Overview== | ||
The structures of two catalytically modified semisynthetic RNases obtained | The structures of two catalytically modified semisynthetic RNases obtained by replacing phenylalanine 120 with leucine and tyrosine have been determined and refined at a resolution of 2.0 A (R = 0.161 and 0.184, respectively). These structures have been compared with the refined 1.8-A structure (R = 0.204) of the fully active phenylalanine-containing enzyme (Martin PD, Doscher MS, Edwards BFP, 1987, J Biol Chem 262:15930-15938) and with the catalytically defective D121A (2.0 A, R = 0.172) and D121N (2.0 A, R = 0.186) analogs (deMel VSJ, Martin PD, Doscher MS, Edwards BFP, 1992, J Biol Chem 267:247-256). The movement away from the active site of the loop containing residues 65-72 is seen in all three catalytically defective analogs--F120L, D121A, and D121N--but not in the fully active (or hyperactive) F120Y. The insertion of the phenolic hydroxyl of Tyr 120 into a hydrogen-bonding network involving the hydroxyl group of Ser 123 and a water molecule in F120Y is the likely basis for the hyperactivity toward uridine 2',3'-cyclic phosphate previously found for this analog (Hodges RS, Merrifield RB, 1974, Int J Pept Protein Res 6:397-405) as well as the threefold increase in KM for cytidine 2',3'-cyclic phosphate found for this analog by ourselves. | ||
==About this Structure== | ==About this Structure== | ||
1SSA is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ] with SO4 as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | 1SSA is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ] with <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SSA OCA]. | ||
==Reference== | ==Reference== | ||
Structural investigation of catalytically modified F120L and F120Y semisynthetic ribonucleases., deMel VS, Doscher MS, Glinn MA, Martin PD, Ram ML, Edwards BF, Protein Sci. 1994 Jan;3(1):39-50. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=8142897 8142897] | Structural investigation of catalytically modified F120L and F120Y semisynthetic ribonucleases., deMel VS, Doscher MS, Glinn MA, Martin PD, Ram ML, Edwards BF, Protein Sci. 1994 Jan;3(1):39-50. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=8142897 8142897] | ||
[[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: Glinn, M | [[Category: Glinn, M A.]] | ||
[[Category: Martin, P | [[Category: Martin, P D.]] | ||
[[Category: Ram, M | [[Category: Ram, M L.]] | ||
[[Category: SO4]] | [[Category: SO4]] | ||
[[Category: hydrolase(endoribonuclease)]] | [[Category: hydrolase(endoribonuclease)]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:04:41 2008'' | ||
