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==THE MOLECULAR AND CRYSTAL STRUCTURES OF MONOCLINIC PORCINE PEPSIN REFINED AT 1.8 ANGSTROMS RESOLUTION== | |||
<StructureSection load='4pep' size='340' side='right'caption='[[4pep]], [[Resolution|resolution]] 1.80Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[4pep]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Pig Pig]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=1pep 1pep]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4PEP OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4PEP FirstGlance]. <br> | |||
</td></tr><tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=SEP:PHOSPHOSERINE'>SEP</scene></td></tr> | |||
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Pepsin_A Pepsin A], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.23.1 3.4.23.1] </span></td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4pep FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4pep OCA], [http://pdbe.org/4pep PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4pep RCSB], [http://www.ebi.ac.uk/pdbsum/4pep PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=4pep ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[[http://www.uniprot.org/uniprot/PEPA_PIG PEPA_PIG]] Shows particularly broad specificity; although bonds involving phenylalanine and leucine are preferred, many others are also cleaved to some extent. | |||
== Evolutionary Conservation == | |||
[[Image:Consurf_key_small.gif|200px|right]] | |||
Check<jmol> | |||
<jmolCheckbox> | |||
<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/pe/4pep_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | |||
<text>to colour the structure by Evolutionary Conservation</text> | |||
</jmolCheckbox> | |||
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=4pep ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The molecular structure of the archetypal aspartic proteinase, porcine pepsin (EC 3.4.23.1), has been refined using data collected from a single monoclinic crystal on a twin multiwire detector system to 1.8 A resolution. The current crystallographic R-factor (= sigma parallel to Fo/-/Fc parallel to/sigma/Fo/) is 0.174 for the 20,519 reflections with /Fo/ greater than or equal to 3 sigma (Fo) in the range 8.0 to 1.8 A (/Fo/ and /Fc/ are the observed and calculated structure factor amplitudes respectively). The refinement has shown conclusively that there are only 326 amino acid residues in porcine pepsin. Ile230 is not present in the molecule. The two catalytic residues Asp32 and Asp215 have dispositions in porcine pepsin very similar to the dispositions of the equivalent residues in the other aspartic proteinases of known structure. A bound solvent molecule is associated with both carboxyl groups at the active site. No bound ethanol molecule could be identified conclusively in the structure. The average thermal motion parameter of the residues that comprise the C-terminal domain of pepsin is approximately twice that of the residues in the N-terminal domain. Comparisons of the tertiary structure of pepsin with porcine pepsinogen, penicillopepsin, rhizopus pepsin and endothia pepsin reveal that the N-terminal domains are topographically more similar than the conformationally flexible C-terminal domains. The conformational differences may be modeled as rigid-body movements of "reduced" C-terminal domains (residues 193 to 212 and 223 to 298 in pepsin numbering). A similar movement of the C-terminal domain of endothia pepsin has been observed upon inhibitor binding. A phosphoryl group covalently attached to Ser68 O gamma has been identified in the electron density map of porcine pepsin. The low pKa1 value for this group, coupled with unusual microenvironments for several of the aspartyl carboxylate groups, ensures a net negative charge on porcine pepsin in a strongly acid medium. Thus, there is a structural explanation for the very early observations of "anodic migration" of porcine pepsin at pH 1. In the crystals, the molecules are packed tightly into a monoclinic unit cell. There are 190 direct contacts (less than or equal to 4.0 A) between a central pepsin molecule and the five unique symmetry-related molecules surrounding it in the crystalline lattice. The tight packing in this cell makes pepsin's active site and binding cleft relatively inaccessible to substrate analogs or inhibitors. | |||
Molecular and crystal structures of monoclinic porcine pepsin refined at 1.8 A resolution.,Sielecki AR, Fedorov AA, Boodhoo A, Andreeva NS, James MN J Mol Biol. 1990 Jul 5;214(1):143-70. PMID:2115087<ref>PMID:2115087</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 4pep" style="background-color:#fffaf0;"></div> | |||
==See Also== | ==See Also== | ||
*[[Pepsin|Pepsin]] | *[[Pepsin|Pepsin]] | ||
== References == | |||
== | <references/> | ||
< | __TOC__ | ||
</StructureSection> | |||
[[Category: Large Structures]] | |||
[[Category: Pepsin A]] | [[Category: Pepsin A]] | ||
[[Category: | [[Category: Pig]] | ||
[[Category: Andreeva, N | [[Category: Andreeva, N]] | ||
[[Category: Fedorov, A A | [[Category: Fedorov, A A]] | ||
[[Category: James, M | [[Category: James, M]] | ||
[[Category: Sielecki, A | [[Category: Sielecki, A]] | ||