1FE5: Sequence And Crystal Structure Of A Basic Phospholipase A2 From Common Krait (bungarus Caeruleus) At 2.4 Resolution: Identification And Characterization Of Its Pharmacological Sites

Citation:
Abstract
This is the first phospholipase A2 (PLA2) structure from the family of kraits. The protein was isolated from Bungarus caeruleus (common krait) and the primary sequence was determined using cDNA approach. Three-dimensional structure of this presynaptic neurotoxic PLA2 from group I has been determined by molecular replacement method using the model of PLA2 component of beta2-bungarotoxin (Bungarus multicinctus) and refined using CNS package to a final R-factor of 20.1 % for all the data in resolution range 20.0-2.4 A. The final refined model comprises 897 protein atoms and 77 water molecules. The overall framework of krait phospholipase A2 with three long helices and two short antiparallel beta-strands is extremely similar to those observed for other group I PLA2s. However, the critical parts of PLA2 folding are concerned with its various functional loops. The conformations of these loops determine the efficiency of enzyme action and presence/absence of various pharmacological functions. In the present structure calcium-binding loop is occupied by a sodium ion with a 7-fold co-ordination. The conformation of loop 55-75 in krait PLA2 corresponds to a very high activity of the enzyme. A comparison of its sequence with multimeric PLA2s clearly shows the absence of critical residues such as Tyr3, Trp61 and Phe64, which are involved in the multimerization of PLA2 molecules. The protein shows anticoagulant and neurotoxic activities.
PDB ID: 1FE5Download
MMDB ID: 15327
PDB Deposition Date: 2000/7/21
Updated in MMDB: 2017/10
Experimental Method:
x-ray diffraction
Resolution: 2.45  Å
Source Organism:
Similar Structures:
Biological Unit for 1FE5: monomeric; determined by author
Molecular Components in 1FE5
Label Count Molecule
Protein (1 molecule)
1
Phospholipase A2
Molecule annotation
Chemical (1 molecule)
1
1
* Click molecule labels to explore molecular sequence information.

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