1s2j: Difference between revisions

Revision as of 08:13, 3 May 2008

Crystal structure of the Drosophila pattern-recognition receptor PGRP-SA

OverviewOverview

The Drosophila peptidoglycan recognition protein SA (PGRP-SA) is critically involved in sensing bacterial infection and activating the Toll signaling pathway, which induces the expression of specific antimicrobial peptide genes. We have determined the crystal structure of PGRP-SA to 2.2-A resolution and analyzed its peptidoglycan (PG) recognition and signaling activities. We found an extended surface groove in the structure of PGRP-SA, lined with residues that are highly diverse among different PGRPs. Mutational analysis identified it as a PG docking groove required for Toll signaling and showed that residue Ser158 is essential for both PG binding and Toll activation. Contrary to the general belief that PGRP-SA has lost enzyme function and serves primarily for PG sensing, we found that it possesses an intrinsic L,D-carboxypeptidase activity for diaminopimelic acid-type tetrapeptide PG fragments but not lysine-type PG fragments, and that Ser158 and His42 may participate in the hydrolytic activity. As L,D-configured peptide bonds exist only in prokaryotes, this work reveals a rare enzymatic activity in a eukaryotic protein known for sensing bacteria and provides a possible explanation of how PGRP-SA mediates Toll activation specifically in response to lysine-type PG.

About this StructureAbout this Structure

1S2J is a Single protein structure of sequence from Drosophila melanogaster. Full crystallographic information is available from OCA.

ReferenceReference

A Drosophila pattern recognition receptor contains a peptidoglycan docking groove and unusual L,D-carboxypeptidase activity., Chang CI, Pili-Floury S, Herve M, Parquet C, Chelliah Y, Lemaitre B, Mengin-Lecreulx D, Deisenhofer J, PLoS Biol. 2004 Sep;2(9):E277. Epub 2004 Sep 7. PMID:15361936 Page seeded by OCA on Sat May 3 08:13:02 2008

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OCA

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 [[Image:1s2j.jpg|left|200px]]
- {{Structure
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-|ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Muramoyltetrapeptide_carboxypeptidase Muramoyltetrapeptide carboxypeptidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.17.13 3.4.17.13] </span>
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-|GENE= PGRP-SA ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=7227 Drosophila melanogaster])
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-}}
 '''Crystal structure of the Drosophila pattern-recognition receptor PGRP-SA'''
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 [[Category: Mengin-Lecreulx, D.]]
 [[Category: Pili-Floury, S.]]
-[[Category: mixed beta-sheet]]
+[[Category: Mixed beta-sheet]]
-[[Category: pi-helix (one turn)]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May  3 08:13:02 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 23:36:29 2008''