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| {{STRUCTURE_1s2j| PDB=1s2j | SCENE= }} | | {{STRUCTURE_1s2j| PDB=1s2j | SCENE= }} |
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| '''Crystal structure of the Drosophila pattern-recognition receptor PGRP-SA'''
| | ===Crystal structure of the Drosophila pattern-recognition receptor PGRP-SA=== |
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| ==Overview==
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| 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. | | The line below this paragraph, {{ABSTRACT_PUBMED_15361936}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 15361936 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_15361936}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Pili-Floury, S.]] | | [[Category: Pili-Floury, S.]] |
| [[Category: Mixed beta-sheet]] | | [[Category: Mixed beta-sheet]] |
| ''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 Mon Jul 28 16:42:00 2008'' |