3d2c | pdb_00003d2c

Structure of 4D3, a thermostable mutant of Bacillus subtilis lipase obtained through directed evolution

spinqualitylabelsall models 3d2c, resolution 2.18Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3d2c is a 12 chain structure with sequence from Bacillus subtilis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 1t2n, 1t4m, 3d2a, 3d2b Gene: lipA, lip, BSU02700 (Bacillus subtilis) Activity: Triacylglycerol lipase, with EC number 3.1.1.3 Resources: FirstGlance, OCA, RCSB, PDBsum 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 PubMed In vitro evolution methods are now being routinely used to identify protein variants with novel and enhanced properties that are difficult to achieve using rational design. However, one of the limitations is in screening for beneficial mutants through several generations due to the occurrence of neutral/negative mutations occurring in the background of positive ones. While evolving a lipase in vitro from mesophilic Bacillus subtilis to generate thermostable variants, we have designed protocols that combine stringent three-tier testing, sequencing and stability assessments on the protein at the end of each generation. This strategy resulted in a total of six stabilizing mutations in just two generations with three mutations per generation. Each of the six mutants when evaluated individually contributed additively to thermostability. A combination of all of them resulted in the best variant that shows a remarkable 15 degrees C shift in melting temperature and a millionfold decrease in the thermal inactivation rate with only a marginal increase of 3 kcal mol(-1) in free energy of stabilization. Notably, in addition to the dramatic shift in optimum temperature by 20 degrees C, the activity has increased two- to fivefold in the temperature range 25-65 degrees C. High-resolution crystal structures of three of the mutants, each with 5 degrees increments in melting temperature, reveal the structural basis of these mutations in attaining higher thermostability. The structures highlight the importance of water-mediated ionic networks on the protein surface in imparting thermostability. Saturation mutagenesis at each of the six positions did not result in enhanced thermostability in almost all the cases, confirming the crucial role played by each mutation as revealed through the structural study. Overall, our study presents an efficient strategy that can be employed in directed evolution approaches employed for obtaining improved properties of proteins. Thermostable Bacillus subtilis lipases: in vitro evolution and structural insight.,Ahmad S, Kamal MZ, Sankaranarayanan R, Rao NM J Mol Biol. 2008 Aug 29;381(2):324-40. Epub 2008 Jul 2. PMID:18599073 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Lipase

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