2qub
Crystal structure of extracellular lipase LipA from Serratia marcescensCrystal structure of extracellular lipase LipA from Serratia marcescens
Structural highlights
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 PubMedLipase LipA from Serratia marcescens is a 613-amino acid enzyme belonging to family I.3 of lipolytic enzymes that has an important biotechnological application in the production of a chiral precursor for the coronary vasodilator diltiazem. Like other family I.3 lipases, LipA is secreted by Gram-negative bacteria via a type I secretion system and possesses 13 copies of a calcium binding tandem repeat motif, GGXGXDXUX (U, hydrophobic amino acids), in the C-terminal part of the polypeptide chain. The 1.8-A crystal structure of LipA reveals a close relation to eukaryotic lipases, whereas family I.1 and I.2 enzymes appear to be more distantly related. Interestingly, the structure shows for the N-terminal lipase domain a variation on the canonical alpha/beta hydrolase fold in an open conformation, where the putative lid helix is anchored by a Ca(2+) ion essential for activity. Another novel feature observed in this lipase structure is the presence of a helical hairpin additional to the putative lid helix that exposes a hydrophobic surface to the aqueous medium and might function as an additional lid. The tandem repeats form two separated parallel beta-roll domains that pack tightly against each other. Variations of the consensus sequence of the tandem repeats within the second beta-roll result in an asymmetric Ca(2+) binding on only one side of the roll. The analysis of the properties of the beta-roll domains suggests an intramolecular chaperone function. A calcium-gated lid and a large beta-roll sandwich are revealed by the crystal structure of extracellular lipase from Serratia marcescens.,Meier R, Drepper T, Svensson V, Jaeger KE, Baumann U J Biol Chem. 2007 Oct 26;282(43):31477-83. Epub 2007 Aug 28. PMID:17728256[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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