Open AccessIsolation, purification, crystallization and preliminary crystallographic studies of sagitoxin, an oligomeric cardiotoxin from the venom of Naja naja saggitifera
Author(s) -
Mir Rafia,
Sinha Mau,
Sharma Sujata,
Singh Nagendra,
Kaur Punit,
Srinivasan A.,
Singh Tej P.
Publication year - 2008
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309108014334
Subject(s) - cardiotoxin , venom , naja , crystallization , isolation (microbiology) , cobra , crystallography , chemistry , materials science , biology , organic chemistry , biochemistry , computer science , bioinformatics , programming language
Sagitoxin, a novel cardiotoxin from the venom of Naja naja saggitifera , has been successfully isolated, purified to homogeneity and crystallized. The toxin was purified using successive separation steps on a CM‐Sephadex C‐50 column and a reverse‐phase column. The 6.75 kDa toxin was sequenced by the Edman method using a PPSQ‐21 protein sequencer. It was crystallized using the hanging‐drop vapour‐diffusion method. The hexagonal‐shaped crystals diffracted to 3.0 Å resolution and belonged to space group P 6 4 , with unit‐cell parameters a = b = 111.1, c = 137.3 Å, γ = 120°. There are 36 molecules in the unit cell, which has an approximate solvent content of 80%. Structure determination revealed that the molecules of sagitoxin associate in a hexameric form and create a pore in the centre which has functional significance.