4LIP: Pseudomonas Lipase Complexed With Rc-(rp, Sp)- Dibutylcarbamoylglycero-3-o-butylphosphonate

Citation:
Abstract
To investigate the enantioselectivity of Pseudomonas cepacia lipase, inhibition studies were performed with Sc- and Rc-(Rp,Sp)-1,2-dialkylcarbamoylglycero-3-O-p-nitrophenyl alkylphosphonates of different alkyl chain lengths. P. cepacia lipase was most rapidly inactivated by Rc-(Rp,Sp)-1,2-dioctylcarbamoylglycero-3-O-p-nitrophenyl octylphosphonate (Rc-trioctyl) with an inactivation half-time of 75 min, while that for the Sc-(Rp,Sp)-1,2-dioctylcarbamoylglycero-3-O-p-nitrophenyl octyl-phosphonate (Sc-trioctyl) compound was 530 min. X-ray structures were obtained of P. cepacia lipase after reaction with Rc-trioctyl to 0.29-nm resolution at pH 4 and covalently modified with Rc-(Rp,Sp)-1,2-dibutylcarbamoylglycero-3-O-p-nitrophenyl butyl-phosphonate (Rc-tributyl) to 0.175-nm resolution at pH 8.5. The three-dimensional structures reveal that both triacylglycerol analogues had reacted with the active-site Ser87, forming a covalent complex. The bound phosphorus atom shows the same chirality (Sp) in both complexes despite the use of a racemic (Rp,Sp) mixture at the phosphorus atom of the triacylglycerol analogues. In the structure of Rc-tributyl-complexed P. cepacia lipase, the diacylglycerol moiety has been lost due to an aging reaction, and only the butyl phosphonate remains visible in the electron density. In the Rc-trioctyl complex the complete inhibitor is clearly defined; it adopts a bent tuning fork conformation. Unambiguously, four binding pockets for the triacylglycerol could be detected: an oxyanion hole and three pockets which accommodate the sn-1, sn-2, and sn-3 fatty acid chains. Van der Waals' interactions are the main forces that keep the radyl groups of the triacylglycerol analogue in position and, in addition, a hydrogen bond to the carbonyl oxygen of the sn-2 chain contributes to fixing the position of the inhibitor.
PDB ID: 4LIPDownload
MMDB ID: 8299
PDB Deposition Date: 1997/8/18
Updated in MMDB: 1998/11
Experimental Method:
x-ray diffraction
Resolution: 1.75  Å
Source Organism:
Similar Structures:
Biological Unit for 4LIP: monomeric; determined by author
Molecular Components in 4LIP
Label Count Molecule
Protein (1 molecule)
1
Triacyl-glycerol-hydrolase
Molecule annotation
Chemicals (2 molecules)
1
1
2
1
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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