|
|
| Line 1: |
Line 1: |
| [[Image:3bf0.jpg|left|200px]] | | {{Seed}} |
| | [[Image:3bf0.png|left|200px]] |
|
| |
|
| <!-- | | <!-- |
| Line 9: |
Line 10: |
| {{STRUCTURE_3bf0| PDB=3bf0 | SCENE= }} | | {{STRUCTURE_3bf0| PDB=3bf0 | SCENE= }} |
|
| |
|
| '''Crystal structure of Escherichia coli Signal peptide peptidase (SppA), Native crystals'''
| | ===Crystal structure of Escherichia coli Signal peptide peptidase (SppA), Native crystals=== |
|
| |
|
|
| |
|
| ==Overview==
| | <!-- |
| Signal peptide peptidase (Spp) is the enzyme responsible for cleaving the remnant signal peptides left behind in the membrane following Sec-dependent protein secretion. Spp activity appears to be present in all cell types, eukaryotic, prokaryotic and archaeal. Here we report the first structure of a signal peptide peptidase, that of the Escherichia coli SppA (SppA(EC)). SppA(EC) forms a tetrameric assembly with a novel bowl-shaped architecture. The bowl has a dramatically hydrophobic interior and contains four separate active sites that utilize a Ser/Lys catalytic dyad mechanism. Our structural analysis of SppA reveals that while in many Gram-negative bacteria as well as characterized plant variants, a tandem duplication in the protein fold creates an intact active site at the interface between the repeated domains, other species, particularly Gram-positive and archaeal organisms, encode half-size, unduplicated SppA variants that could form similar oligomers to their duplicated counterparts, but using an octamer arrangement and with the catalytic residues provided by neighboring monomers. The structure reveals a similarity in the protein fold between the domains in the periplasmic Ser/Lys protease SppA and the monomers seen in the cytoplasmic Ser/His/Asp protease ClpP. We propose that SppA may, in addition to its role in signal peptide hydrolysis, have a role in the quality assurance of periplasmic and membrane-bound proteins, similar to the role that ClpP plays for cytoplasmic proteins.
| | The line below this paragraph, {{ABSTRACT_PUBMED_18164727}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 18164727 is the PubMed ID number. |
| | --> |
| | {{ABSTRACT_PUBMED_18164727}} |
|
| |
|
| ==About this Structure== | | ==About this Structure== |
| Line 30: |
Line 34: |
| [[Category: Ser/lys protease]] | | [[Category: Ser/lys protease]] |
| [[Category: Transmembrane]] | | [[Category: Transmembrane]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 20:42:17 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Jul 27 12:23:26 2008'' |
