 |
|
Title
|
|
Erabutoxin b. Initial protein refinement and sequence analysis at 0.140-nm resolution.
|
|
|
Authors
|
|
P.E.Bourne,
A.Sato,
P.W.Corfield,
L.S.Rosen,
S.Birken,
B.W.Low.
|
|
|
Ref.
|
|
Eur J Biochem, 1985,
153,
521-527.
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
The crystal structure of the protein postsynaptic neurotoxin, erabutoxin b, has
been refined at 0.140-nm resolution (R = 0.22) by restrained least-squares and
interactive computer graphics. The study has established complete structural
identity of the two sea-snake venom toxins, erabutoxin b and neurotoxin b,
isolated from Laticauda semifasciata snakes taken in different Pacific Ocean
waters. Two chemical-sequence inversion errors in erabutoxin b have been
discovered during refinement, corrected and subsequently confirmed in both
erabutoxin b and erabutoxin a by chemical analysis. The correct sequences are
His6-Gln7, hitherto unsuspected, and Ser18-Pro19. The sequence correction
His6-Gln7 explains the anomalous results of 1H NMR solution studies and those of
early chemical modification experiments, which were in conflict with the
previously published three-dimensional structure of erabutoxin b. On refinement,
the five-stranded beta sheet described earlier is now shown to be discontinuous,
split into a two-stranded beta loop and a three-stranded beta sheet. Unique
features of the Pro44-Gly49 peripheral segment have now been identified. 51
water molecule positions have been located.
|
|
|
|