1ild
From Proteopedia
OUTER MEMBRANE PHOSPHOLIPASE A FROM ESCHERICHIA COLI N156A ACTIVE SITE MUTANT pH 4.6
Structural highlights
FunctionPA1_ECOLI Has broad substrate specificity including hydrolysis of phosphatidylcholine with phospholipase A2 (EC 3.1.1.4) and phospholipase A1 (EC 3.1.1.32) activities. Strong expression leads to outer membrane breakdown and cell death; is dormant in normal growing cells. Required for efficient secretion of bacteriocins. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedOuter membrane phospholipase A (OMPLA) from Escherichia coli is an integral-membrane enzyme with a unique His-Ser-Asn catalytic triad. In serine proteases and serine esterases usually an Asp occurs in the catalytic triad; its role has been the subject of much debate. Here the role of the uncharged asparagine in the active site of OMPLA is investigated by structural characterization of the Asn156Ala mutant. Asparagine 156 is not involved in maintaining the overall active-site configuration and does not contribute significantly to the thermal stability of OMPLA. The active-site histidine retains an active conformation in the mutant notwithstanding the loss of the hydrogen bond to the asparagine side chain. Instead, stabilization of the correct tautomeric form of the histidine can account for the observed decrease in activity of the Asn156Ala mutant. Structural investigations of the active-site mutant Asn156Ala of outer membrane phospholipase A: function of the Asn-His interaction in the catalytic triad.,Snijder HJ, Van Eerde JH, Kingma RL, Kalk KH, Dekker N, Egmond MR, Dijkstra BW Protein Sci. 2001 Oct;10(10):1962-9. PMID:11567087[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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