Heat-labile enterotoxin crystal forms with variable A/B5 orientation. Analysis of conformational flexibility.
A new native crystal form of heat-labile enterotoxin (LT) has two AB5 complexes in the asymmetric unit with different orientations of the A subunit with respect to the B pentamer. Comparison with other crystal forms of LT shows that there is considerable conformational freedom for orientating the A subunit with respect to the B pentamer. The rotations of A in different crystal forms do not follow one specific axis, but most of them share a hinge point, close to the main interaction area between A and B5. Analysis of the two high-resolution structures available shows that these rotations cause very little change in the actual interactions between A and B5.
Sixma
T K
TK
BIOSON Research Institute, University of Groningen, The Netherlands.
Aguirre
A
A
Terwisscha van Scheltinga
A C
AC
Wartna
E S
ES
Kalk
K H
KH
Hol
W G
WG
D001427:Bacterial Toxins / Q000737:chemistry*; D003460:Crystallization; D004768:Enterotoxins / Q000737:chemistry*; D004926:Escherichia coli / Q000737:chemistry*; D029968:Escherichia coli Proteins; D046911:Macromolecular Substances; D011487:Protein Conformation; D014961:X-Ray Diffraction
D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D046911:Macromolecular Substances; C027538:heat-labile enterotoxin, E coli