3psg: Difference between revisions
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New page: left|200px<br /> <applet load="3psg" size="450" color="white" frame="true" align="right" spinBox="true" caption="3psg, resolution 1.65Å" /> '''THE HIGH RESOLUTION... |
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[[Image:3psg.gif|left|200px]]<br /> | [[Image:3psg.gif|left|200px]]<br /><applet load="3psg" size="350" color="white" frame="true" align="right" spinBox="true" | ||
<applet load="3psg" size=" | |||
caption="3psg, resolution 1.65Å" /> | caption="3psg, resolution 1.65Å" /> | ||
'''THE HIGH RESOLUTION CRYSTAL STRUCTURE OF PORCINE PEPSINOGEN'''<br /> | '''THE HIGH RESOLUTION CRYSTAL STRUCTURE OF PORCINE PEPSINOGEN'''<br /> | ||
==Overview== | ==Overview== | ||
The structure of porcine pepsinogen at pH 6.1 has been refined to an | The structure of porcine pepsinogen at pH 6.1 has been refined to an R-factor of 0.173 for data extending to 1.65 A. The final model contains 180 solvent molecules and lacks density for residues 157-161. The structure of this aspartic proteinase zymogen possesses many of the characteristics of pepsin, the mature enzyme. The secondary structure of the zymogen consists predominantly of beta-sheet, with an approximate 2-fold axis of symmetry. The activation peptide packs into the active site cleft, and the N-terminus (1P-9P) occupies the position of the mature N-terminus (1-9). Thus changes upon activation include excision of the activation peptide and proper relocation of the mature N-terminus. The activation peptide or residues of the displaced mature N-terminus make specific interactions with the substrate binding subsites. The active site of pepsinogen is intact; thus the lack of activity of pepsinogen is not due to a deformation of the active site. Nine ion pairs in pepsinogen may be important in the advent of activation and involve the activation peptide or regions of the mature N-terminus which are relocated in the mature enzyme. The activation peptide-pepsin junction, 44P-1, is characterized by high thermal parameters and weak density, indicating a flexible structure which would be accessible to cleavage. Pepsinogen is an appropriate model for the structures of other zymogens in the aspartic proteinase family. | ||
==About this Structure== | ==About this Structure== | ||
3PSG is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Sus_scrofa Sus scrofa]. This structure | 3PSG is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Sus_scrofa Sus scrofa]. This structure supersedes the now removed PDB entry 1PSG. The following page contains interesting information on the relation of 3PSG with [[http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb12_1.html Pepsin]]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3PSG OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Sus scrofa]] | [[Category: Sus scrofa]] | ||
[[Category: Hartsuck, J | [[Category: Hartsuck, J A.]] | ||
[[Category: Koelsch, G.]] | [[Category: Koelsch, G.]] | ||
[[Category: Remington, S | [[Category: Remington, S J.]] | ||
[[Category: hydrolase(acid proteinase zymogen)]] | [[Category: hydrolase(acid proteinase zymogen)]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 19:10:58 2008'' | ||