Isolation, purification, crystallization and preliminary crystallographic studies of sagitoxin, an oligomeric cardiotoxin from the venom of Naja naja saggitifera.
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 A resolution and belonged to space group P6(4), with unit-cell parameters a = b = 111.1, c = 137.3 A, gamma = 120 degrees . 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.
Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110 029, India.
Rafia
R
Mir
Mau
M
Sinha
Sujata
S
Sharma
Nagendra
N
Singh
Punit
P
Kaur
A
A
Srinivasan
Tej P
TP
Singh
D000595:Amino Acid Sequence; D000818:Animals; D054715:Cardiotoxins / Q000737:chemistry* / Q000145:classification / Q000302:isolation & purification* / Q000633:toxicity; D003460:Crystallization; D018360:Crystallography, X-Ray; D004546:Elapid Venoms / Q000737:chemistry*; D017815:Elapidae; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009842:Oligopeptides / Q000737:chemistry; D017433:Protein Structure, Secondary
D054715:Cardiotoxins; D004546:Elapid Venoms; D009842:Oligopeptides