1FW2

OUTER MEMBRANE PHOSPHOLIPASE A FROM ESCHERICHIA COLI

Summary for 1FW2

• Entry DOI: 10.2210/pdb1fw2/pdb
• Related: 1QD5 1QD6
• Descriptor: OUTER MEMBRANE PHOSPHOLIPASE A, CALCIUM ION (3 entities in total)
• Functional Keywords: anti-parallel beta barrel dimer, membrane protein, hydrolase
• Biological source: Escherichia coli
• Cellular location: Cell outer membrane; Multi-pass membrane protein: P0A921
• Total number of polymer chains: 1
• Total formula weight: 31576.95

Authors

Snijder, H.J.,Kingma, R.L.,Kalk, K.H.,Dekker, N.,Egmond, M.R.,Dijkstra, B.W. (deposition date: 2000-09-21, release date: 2001-06-01, Last modification date: 2024-05-22)

Primary citation

Snijder, H.J.,Kingma, R.L.,Kalk, K.H.,Dekker, N.,Egmond, M.R.,Dijkstra, B.W.
Structural investigations of calcium binding and its role in activity and activation of outer membrane phospholipase A from Escherichia coli.
J.Mol.Biol., 309:477-489, 2001

PubMed Abstract: 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.

PubMed: 11371166
DOI: 10.1006/jmbi.2001.4675

Experimental method

X-RAY DIFFRACTION (2.6 Å)