GONUTS has been updated to MW1.31 Most things seem to be working but be sure to report problems.

Have any questions? Please email us at ecoliwiki@gmail.com

PMID:11371166

From GONUTS
Jump to: navigation, search
Citation

Snijder, HJ, Kingma, RL, Kalk, KH, Dekker, N, Egmond, MR and Dijkstra, BW (2001) Structural investigations of calcium binding and its role in activity and activation of outer membrane phospholipase A from Escherichia coli. J. Mol. Biol. 309:477-89

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.

Links

PubMed Online version:10.1006/jmbi.2001.4675

Keywords

Amino Acid Motifs; Amino Acid Sequence; Bacterial Outer Membrane Proteins/chemistry; Bacterial Outer Membrane Proteins/metabolism; Binding Sites; Calcium/metabolism; Calcium/pharmacology; Consensus Sequence; Conserved Sequence; Crystallography, X-Ray; Dimerization; Enzyme Activation/drug effects; Escherichia coli/enzymology; Evolution, Molecular; Models, Molecular; Molecular Sequence Data; Phospholipases A/chemistry; Phospholipases A/metabolism; Phospholipases A1; Protein Binding; Protein Structure, Quaternary; Sequence Alignment

Significance

Annotations

Gene product Qualifier GO Term Evidence Code with/from Aspect Extension Notes Status

ECOLI:PA1

located_in

GO:0031230: intrinsic component of cell outer membrane

ECO:0000314: direct assay evidence used in manual assertion

C

Seeded From UniProt

complete

ECOLI:PA1

enables

GO:0042803: protein homodimerization activity

ECO:0000314: direct assay evidence used in manual assertion

F

Seeded From UniProt

complete

ECOLI:PA1

part_of

GO:0031230: intrinsic component of cell outer membrane

ECO:0000314: direct assay evidence used in manual assertion

C

Seeded From UniProt

complete

ECOLI:PA1

enables

GO:0005509: calcium ion binding

ECO:0000314: direct assay evidence used in manual assertion

F

Seeded From UniProt

complete

ECOLI:PA1

enables

GO:0008970: phospholipase A1 activity

ECO:0000304: author statement supported by traceable reference used in manual assertion

F

Seeded From UniProt

complete

ECOLI:PA1

enables

GO:0004623: phospholipase A2 activity

ECO:0000304: author statement supported by traceable reference used in manual assertion

F

Seeded From UniProt

complete


See also

References

See Help:References for how to manage references in GONUTS.