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1z5f
From Proteopedia
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'''Solution Structure of the Cytotoxic RC-RNase 3 with a Pyroglutamate Residue at the N-terminus''' | '''Solution Structure of the Cytotoxic RC-RNase 3 with a Pyroglutamate Residue at the N-terminus''' | ||
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[[Category: Lou, Y C.]] | [[Category: Lou, Y C.]] | ||
[[Category: Pan, Y R.]] | [[Category: Pan, Y R.]] | ||
| - | [[Category: | + | [[Category: Bullfrog]] |
| - | [[Category: | + | [[Category: Cytotoxicity]] |
| - | [[Category: | + | [[Category: Nmr]] |
| - | [[Category: | + | [[Category: Pyroglutamate]] |
| - | [[Category: | + | [[Category: Ribonuclease]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 17:11:51 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 14:11, 3 May 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 Sat May 3 17:11:51 2008
Categories: Rana catesbeiana | Single protein | Chen, C. | Huang, Y C. | Liao, Y D. | Lou, Y C. | Pan, Y R. | Bullfrog | Cytotoxicity | Nmr | Pyroglutamate | Ribonuclease
