View source for 1keh

==Precursor structure of cephalosporin acylase==
<StructureSection load='1keh' size='340' side='right' caption='[[1keh]], [[Resolution|resolution]] 2.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1keh]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Aj_2067 Aj 2067]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KEH OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1KEH FirstGlance]. <br>
</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=1keh FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1keh OCA], [http://pdbe.org/1keh PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1keh RCSB], [http://www.ebi.ac.uk/pdbsum/1keh PDBsum]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/G7AC_BREDI G7AC_BREDI]] Catalyzes the deacylation of 7 beta-(4-carboxybutanamido)cephalosporanic acid (glutaryl-7-aminocephalosporanic acid or GL-7-ACA) to 7-aminocephalosporanic acid (7-ACA). Can not efficiently use cephalosporin C (CPC), penicillin G, or ampicillin as substrates.<ref>PMID:11080627</ref>  
== 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/ke/1keh_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=1keh ConSurf].
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== Publication Abstract from PubMed ==
Autocatalytic proteolytic cleavage is a frequently observed post-translational modification in proteins. Cephalosporin acylase (CA) is a recently identified member of the N-terminal hydrolase family that is activated from an inactive precursor by autoproteolytic processing, generating a new N-terminal residue, which is either a Ser or a Thr. The N-terminal Ser or Thr becomes a nucleophilic catalytic center for intramolecular and intermolecular amide cleavages. The gene structure of the open reading frame of CAs generally consists of a signal peptide followed by the alpha-subunit, a spacer sequence, and the beta-subunit, which are all translated into a single polypeptide chain, the CA precursor. The precursor is post-translationally modified into an active heterodimeric enzyme with alpha- and beta-subunits, first by intramolecular cleavage and second by intermolecular cleavage. We solved the first CA precursor structure (code 1KEH) from a class I CA from Pseudomonas diminuta at a 2.5-A resolution that provides insight into the mechanism of intramolecular cleavage. A conserved water molecule, stabilized by four hydrogen bonds in unusual pseudotetrahedral geometry, plays a key role to assist the OG atom of Ser(1beta) to generate a strong nucleophile. In addition, the site of the secondary intermolecular cleavage of CA is proposed to be the carbonyl carbon of Gly(158alpha) (Kim, S., and Kim, Y., (2001) J. Biol. Chem., 276, 48376-48381), which is different from the situation in two other class I CAs.

Precursor structure of cephalosporin acylase. Insights into autoproteolytic activation in a new N-terminal hydrolase family.,Kim Y, Kim S, Earnest TN, Hol WG J Biol Chem. 2002 Jan 25;277(4):2823-9. Epub 2001 Nov 8. PMID:11706000<ref>PMID:11706000</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1keh" style="background-color:#fffaf0;"></div>

==See Also==
*[[Cephalosporin acylase|Cephalosporin acylase]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Aj 2067]]
[[Category: Kim, S]]
[[Category: Kim, Y]]
[[Category: Cephalosporin acylase]]
[[Category: Glutaryl-7-aca]]
[[Category: Hydrolase]]
[[Category: Precursor]]