1z5f: Difference between revisions
New page: left|200px<br /><applet load="1z5f" size="450" color="white" frame="true" align="right" spinBox="true" caption="1z5f" /> '''Solution Structure of the Cytotoxic RC-RNase... |
No edit summary |
||
| Line 1: | Line 1: | ||
[[Image:1z5f.gif|left|200px]]<br /><applet load="1z5f" size=" | [[Image:1z5f.gif|left|200px]]<br /><applet load="1z5f" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1z5f" /> | caption="1z5f" /> | ||
'''Solution Structure of the Cytotoxic RC-RNase 3 with a Pyroglutamate Residue at the N-terminus'''<br /> | '''Solution Structure of the Cytotoxic RC-RNase 3 with a Pyroglutamate Residue at the N-terminus'''<br /> | ||
==Overview== | ==Overview== | ||
Many proteins and bioactive peptides contain an N-terminal pyroglutamate | Many proteins and bioactive peptides contain an N-terminal pyroglutamate residue (Pyr1). This residue reduces the susceptibility of the protein to aminopeptidases and often has important functional roles. The antitumor ribonuclease RC-RNase 3 (RNase 3) from oocytes of Rana catesbeiana (bullfrog) is one such protein. We have produced recombinant RNase 3 containing the N-terminal Pyr1 (pRNase 3) and found it to be indistinguishable from the native RNase 3 by mass spectrometry and a variety of other biochemical and immunological criteria. We demonstrated by NMR analysis that the Pyr1 of pRNase 3 forms hydrogen bonds with Lys9 and Ile96 and stabilizes the N-terminal alpha-helix in a rigid conformation. In contrast, the N-terminal alpha-helix becomes flexible and the pKa values of the catalytic residues His10 and His97 altered when Pyr1 formation is blocked by an extra methionine at the N terminus in the recombinant mqRNase 3. Thus, our results provide a mechanistic explanation on the essential role of Pyr1 in maintaining the structural integrity, especially at the N-terminal alpha-helix, and in providing the proper environment for the ionization of His10 and His97 residues for catalysis and cytotoxicity against HeLa cells. | ||
==About this Structure== | ==About this Structure== | ||
1Z5F is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rana_catesbeiana Rana catesbeiana]. Full crystallographic information is available from [http:// | 1Z5F is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rana_catesbeiana Rana catesbeiana]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1Z5F OCA]. | ||
==Reference== | ==Reference== | ||
| Line 14: | Line 14: | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Chen, C.]] | [[Category: Chen, C.]] | ||
[[Category: Huang, Y | [[Category: Huang, Y C.]] | ||
[[Category: Liao, Y | [[Category: Liao, Y D.]] | ||
[[Category: Lou, Y | [[Category: Lou, Y C.]] | ||
[[Category: Pan, Y | [[Category: Pan, Y R.]] | ||
[[Category: bullfrog]] | [[Category: bullfrog]] | ||
[[Category: cytotoxicity]] | [[Category: cytotoxicity]] | ||
| 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 16:12:15 2008'' | ||
Revision as of 14:12, 21 February 2008
|
Solution Structure of the Cytotoxic RC-RNase 3 with a Pyroglutamate Residue at the N-terminus
Overview
Many proteins and bioactive peptides contain an N-terminal pyroglutamate residue (Pyr1). This residue reduces the susceptibility of the protein to aminopeptidases and often has important functional roles. The antitumor ribonuclease RC-RNase 3 (RNase 3) from oocytes of Rana catesbeiana (bullfrog) is one such protein. We have produced recombinant RNase 3 containing the N-terminal Pyr1 (pRNase 3) and found it to be indistinguishable from the native RNase 3 by mass spectrometry and a variety of other biochemical and immunological criteria. We demonstrated by NMR analysis that the Pyr1 of pRNase 3 forms hydrogen bonds with Lys9 and Ile96 and stabilizes the N-terminal alpha-helix in a rigid conformation. In contrast, the N-terminal alpha-helix becomes flexible and the pKa values of the catalytic residues His10 and His97 altered when Pyr1 formation is blocked by an extra methionine at the N terminus in the recombinant mqRNase 3. Thus, our results provide a mechanistic explanation on the essential role of Pyr1 in maintaining the structural integrity, especially at the N-terminal alpha-helix, and in providing the proper environment for the ionization of His10 and His97 residues for catalysis and cytotoxicity against HeLa cells.
About this Structure
1Z5F is a Single protein structure of sequence from Rana catesbeiana. Full crystallographic information is available from OCA.
Reference
Roles of N-terminal pyroglutamate in maintaining structural integrity and pKa values of catalytic histidine residues in bullfrog ribonuclease 3., Lou YC, Huang YC, Pan YR, Chen C, Liao YD, J Mol Biol. 2006 Jan 20;355(3):409-21. Epub 2005 Nov 10. PMID:16309702
Page seeded by OCA on Thu Feb 21 16:12:15 2008
