2qub | pdb_00002qub
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Crystal structure of extracellular lipase LipA from Serratia marcescens
Overview
Lipase 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.
About this Structure
2QUB is a Single protein structure of sequence from Serratia marcescens with CA as ligand. Active as Triacylglycerol lipase, with EC number 3.1.1.3 Known structural/functional Sites: AC1, AC2, AC3, AC4, AC5, AC6, AC7, AC8, AC9, BC1, BC2, BC3, BC4, BC5, BC6, BC7, BC8, BC9, CC1, CC2, CC3, CC4, CC5, CC6, CC7, CC8, CC9, DC1, DC2, DC3, DC4, DC5, DC6, DC7, DC8, DC9, EC1, EC2, EC3, EC4, EC5, EC6, EC7, EC8, EC9, FC1, FC2 and FC3. Full crystallographic information is available from OCA.
Reference
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
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