1fw3: Difference between revisions
New page: left|200px<br /><applet load="1fw3" size="450" color="white" frame="true" align="right" spinBox="true" caption="1fw3, resolution 2.80Å" /> '''OUTER MEMBRANE PHOSP... |
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[[Image:1fw3.jpg|left|200px]]<br /><applet load="1fw3" size=" | [[Image:1fw3.jpg|left|200px]]<br /><applet load="1fw3" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1fw3, resolution 2.80Å" /> | caption="1fw3, resolution 2.80Å" /> | ||
'''OUTER MEMBRANE PHOSPHOLIPASE A FROM ESCHERICHIA COLI'''<br /> | '''OUTER MEMBRANE PHOSPHOLIPASE A FROM ESCHERICHIA COLI'''<br /> | ||
==Overview== | ==Overview== | ||
Outer membrane phospholipase A (OMPLA) is an integral membrane enzyme that | Outer membrane phospholipase A (OMPLA) is an integral membrane enzyme that catalyses the hydrolysis of phospholipids. Enzymatic activity is regulated by reversible dimerisation and calcium-binding. We have investigated the role of calcium by X-ray crystallography. In monomeric OMPLA, one calcium ion binds between two external loops (L3L4 site) at 10 A from the active site. After dimerisation, a new calcium-binding site (catalytic site) is formed at the dimer interface in the active site of each molecule at 6 A from the L3L4 calcium site. The close spacing and the difference in calcium affinity of both sites suggests that the L3L4 site may function as a storage site for a calcium ion, which relocates to the catalytic site upon dimerisation. A sequence alignment demonstrates conservation of the catalytic calcium site but evolutionary variation of the L3L4 site. The residues in the dimer interface are conserved as well, suggesting that all outer membrane phospholipases require dimerisation and calcium in the catalytic site for activity. For this family of phospholipases, we have characterised a consensus sequence motif (YTQ-X(n)-G-X(2)-H-X-SNG) that contains conserved residues involved in dimerisation and catalysis. | ||
==About this Structure== | ==About this Structure== | ||
1FW3 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Active as [http://en.wikipedia.org/wiki/Phospholipase_A(1) Phospholipase A(1)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.1.32 3.1.1.32] Full crystallographic information is available from [http:// | 1FW3 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Active as [http://en.wikipedia.org/wiki/Phospholipase_A(1) Phospholipase A(1)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.1.32 3.1.1.32] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1FW3 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Dekker, N.]] | [[Category: Dekker, N.]] | ||
[[Category: Dijkstra, B | [[Category: Dijkstra, B W.]] | ||
[[Category: Egmond, M | [[Category: Egmond, M R.]] | ||
[[Category: Kalk, K | [[Category: Kalk, K H.]] | ||
[[Category: Kingma, R | [[Category: Kingma, R L.]] | ||
[[Category: Snijder, H | [[Category: Snijder, H J.]] | ||
[[Category: anti-parallel beta barrel dimer]] | [[Category: anti-parallel beta barrel dimer]] | ||
[[Category: membrane protein]] | [[Category: membrane protein]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:43:13 2008'' | ||
Revision as of 13:43, 21 February 2008
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OUTER MEMBRANE PHOSPHOLIPASE A FROM ESCHERICHIA COLI
OverviewOverview
Outer membrane phospholipase A (OMPLA) is an integral membrane enzyme that catalyses the hydrolysis of phospholipids. Enzymatic activity is regulated by reversible dimerisation and calcium-binding. We have investigated the role of calcium by X-ray crystallography. In monomeric OMPLA, one calcium ion binds between two external loops (L3L4 site) at 10 A from the active site. After dimerisation, a new calcium-binding site (catalytic site) is formed at the dimer interface in the active site of each molecule at 6 A from the L3L4 calcium site. The close spacing and the difference in calcium affinity of both sites suggests that the L3L4 site may function as a storage site for a calcium ion, which relocates to the catalytic site upon dimerisation. A sequence alignment demonstrates conservation of the catalytic calcium site but evolutionary variation of the L3L4 site. The residues in the dimer interface are conserved as well, suggesting that all outer membrane phospholipases require dimerisation and calcium in the catalytic site for activity. For this family of phospholipases, we have characterised a consensus sequence motif (YTQ-X(n)-G-X(2)-H-X-SNG) that contains conserved residues involved in dimerisation and catalysis.
About this StructureAbout this Structure
1FW3 is a Single protein structure of sequence from Escherichia coli. Active as Phospholipase A(1), with EC number 3.1.1.32 Full crystallographic information is available from OCA.
ReferenceReference
Structural investigations of calcium binding and its role in activity and activation of outer membrane phospholipase A from Escherichia coli., Snijder HJ, Kingma RL, Kalk KH, Dekker N, Egmond MR, Dijkstra BW, J Mol Biol. 2001 Jun 1;309(2):477-89. PMID:11371166
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