(Below N is a link to NCBI taxonomic web page and E link to ESTHER at designed phylum.) > cellular organisms: NE > Bacteria: NE > Terrabacteria group: NE > Firmicutes: NE > Bacilli: NE > Bacillales: NE > Bacillaceae: NE > Bacillus: NE > Bacillus coagulans: NE
Warning: This entry is a compilation of different species or line or strain with more than 90% amino acide identity. You can retrieve all strain data
(Below N is a link to NCBI taxonomic web page and E link to ESTHER at designed phylum.) Bacillus coagulans DSM 1 = ATCC 7050: N, E.
Bacillus coagulans 36D1: N, E.
Bacillus coagulans 2-6: N, E.
LegendThis sequence has been compared to family alignement (MSA) red => minority aminoacid blue => majority aminoacid color intensity => conservation rate title => sequence position(MSA position)aminoacid rate Catalytic site Catalytic site in the MSA MAFQELSFQSFNGKDNVKAWIYTPIRKPRGIVQVVHGFGEHSRRYLHMIL KFNEAGFVVAADDHVGHGKTAYDSGNWGDWGDKGYMTMAEDEHTLRKIVQ EQYPDLPYFMFGHSMGSMIARGYAATHGAGLSGLILCGTSGRFPNASKLL PVLKNLIYEGKGQETDLSYLEELMGWMTERIEQPKTPNDWISSDPDIVAD HANDPFNNFTTPPNIRSLYYFVQMMEIIVGTEWAEKVPVSIPIYNIAGDQ DPVGQYGEGVYAVSNWLVQTGHHVKTKVYPGHRHEIHNDRDIRDEVEEGI ISFINGIIVK
Microbial carboxylesterases are important biocatalysts that selectively hydrolyze an extensive range of esters. Here, we report the biochemical and structural characterization of an atypical carboxylesterase from Bacillus coagulans (BCE), endowed with high enantioselectivity toward different 1,2-O-isopropylideneglycerol (IPG or solketal) esters. BCE efficiently catalyzes the production of enantiopure (S)-IPG, a chiral building block for the synthesis of beta-blockers, glycerophospholipids, and prostaglandins; efficient hydrolysis was observed up to 65 degrees C. To gain insight into the mechanistic bases of such enantioselectivity, we solved the crystal structures of BCE in apo- and glycerol-bound forms at resolutions of 1.9 and 1.8 A, respectively. In silico docking studies on the BCE structure confirmed that IPG esters with small acyl chains (\<= C6) were easily accommodated in the active site pocket, indicating that small conformational changes are necessary to accept longer substrates. Furthermore, docking studies suggested that enantioselectivity may be due to an improved stabilization of the tetrahedral reaction intermediate for the S-enantiomer. Contrary to the above functional data implying nonlipolytic functions, BCE displays a lipase-like 3D structure that hosts a "lid" domain capping the main entrance to the active site. In lipases the lid mediates catalysis through interfacial activation, a process that we did not observe for BCE. Overall, we present the functional-structural properties of an atypical carboxyl esterase that has nonlipase-like functions, yet possesses a lipase-like 3D fold. Our data provide original enzymatic information in view of BCE applications as an inexpensive, efficient biocatalyst for the production of enantiopure (S)-IPG. DATABASE: Coordinates and structure factors have been deposited in the Protein Data Bank (www.rcsb.org) under accession numbers 5O7G (apo-BCE) and 5OLU (glycerol-bound BCE).
Title: Enhanced enantioselectivity of Bacillus coagulans in the hydrolysis of 1,2-O-isopropylidene glycerol esters by thermal knock-out of undesired enzymes Romano D, Falcioni F, Mora D, Molinari F, Buthe A, Ansorge-Schumacher M Ref: Tetrahedron Asymmetry, 16:841, 2005 : PubMed
The enantioselective hydrolysis of different (RS)-1,2-O-isopropylidene glycerol esters has been achieved with whole cells of Bacillus coagulans NCIMB 9365 furnishing the (S)-alcohol as the major enantiomer. The reaction is catalysed by a thermostable cell-bound carboxylesterase and improvement of the enantioselectivity has been achieved by heat treatment of the whole cells, which causes the knock-outs a non-enantioselective competing enzyme. Thermally-treated cells hydrolysed (RS)-1,2-O-isopropylidene glycerol esters with high enantioselectivity, the highest enantiomeric ratio (80100) being observed for the benzoate. The biocatalyst displayed good stability and could be re-used after filtration for 12 cycles before showing significant loss of activity; repeated biotransformation batches allowed the recovery of 9.55 g/L of enantiomerically pure (S)-isopropylideneglycerol benzoate starting from 24.0 g/L of the racemic mixture.
Bacillus coagulans highly thermostable carboxyl esterase
