TY - JOUR
T1 - A comparison of the crystallographic structures of two catalytic antibodies with esterase activity
AU - Buchbinder, Jenny L.
AU - Stephenson, Robert C.
AU - Scanlan, Thomas S.
AU - Fletterick, Robert J.
N1 - Funding Information:
This work was supported by grants from NIH (GM50672) and NSF (MCB-9513300). T.S.S. is an Alfred P. Sloan research fellow.
PY - 1998/10/9
Y1 - 1998/10/9
N2 - The crystallographic structure of the Fab fragment of the catalytic antibody, 29G11, complexed with an (S)-norleucine phenyl phosphonate transition state analog was determined at 2.2 Å resolution. The antibody catalyzes the hydrolysis of norleucine phenyl ester with (S)-enantioselectivity. The shape and charge complementarity of the binding pocket for the hapten account for the preferential binding of the (S)-enantiomer of the substrate. The structure is compared to that of the more catalytically efficient antibody, 17E8, induced by the same hapten transition state analog. 29G11 has different residues from 17E8 at eight positions in the heavy chain, including four substitutions in the hapten-binding pocket: A33V, S95G, S99R and Y100(A)N, and four substitutions at positions remote from the catalytic site, I28T, R40K, V65G and F91L. The two antibodies show large differences in the orientations of their variable and constant domains, reflected by a 32°difference in their elbow angles. The V(L) and V(H) domains in the two antibodies differ by a rotation of 8.8°. The hapten binds in similar orientations and locations in 29G11 and 17E8, which appear to have catalytic groups in common, though the changes in the association of the variable domains affect the precise positioning of residues in the hapten-binding pocket.
AB - The crystallographic structure of the Fab fragment of the catalytic antibody, 29G11, complexed with an (S)-norleucine phenyl phosphonate transition state analog was determined at 2.2 Å resolution. The antibody catalyzes the hydrolysis of norleucine phenyl ester with (S)-enantioselectivity. The shape and charge complementarity of the binding pocket for the hapten account for the preferential binding of the (S)-enantiomer of the substrate. The structure is compared to that of the more catalytically efficient antibody, 17E8, induced by the same hapten transition state analog. 29G11 has different residues from 17E8 at eight positions in the heavy chain, including four substitutions in the hapten-binding pocket: A33V, S95G, S99R and Y100(A)N, and four substitutions at positions remote from the catalytic site, I28T, R40K, V65G and F91L. The two antibodies show large differences in the orientations of their variable and constant domains, reflected by a 32°difference in their elbow angles. The V(L) and V(H) domains in the two antibodies differ by a rotation of 8.8°. The hapten binds in similar orientations and locations in 29G11 and 17E8, which appear to have catalytic groups in common, though the changes in the association of the variable domains affect the precise positioning of residues in the hapten-binding pocket.
KW - Catalytic antibody
KW - Esterase
KW - Structure
KW - Transition state analog
KW - X-ray crystallography
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U2 - 10.1006/jmbi.1998.2025
DO - 10.1006/jmbi.1998.2025
M3 - Article
C2 - 9753552
AN - SCOPUS:0032500701
SN - 0022-2836
VL - 282
SP - 1033
EP - 1041
JO - Journal of molecular biology
JF - Journal of molecular biology
IS - 5
ER -