K.He
et al.
(2016).
Crystal Structure of the Fab Fragment of an Anti-ofloxacin Antibody and Exploration of Its Specific Binding.
J Agric Food Chem,
64,
2627-2634.
PubMed id: 26963935
DOI: 10.1021/acs.jafc.5b05882
Crystal Structure of the Fab Fragment of an Anti-ofloxacin Antibody and Exploration of Its Specific Binding.
K.He,
X.Du,
W.Sheng,
X.Zhou,
J.Wang,
S.Wang.
ABSTRACT
The limited knowledge on the mechanism of interactions between small
contaminants and the corresponding antibodies greatly inhibits the development
of enzyme-linked immunosorbent assay methods. In this study, the crystal
structure of a Fab fragment specific for ofloxacin was obtained. On the basis of
the crystal characteristics, the modeling of the interactions between ofloxacin
and the Fab revealed that TYR31 and HIS99 of the heavy chain and MET20 and GLN79
of the light chain formed a hydrophobic region and that SER52 and ALA97 of the
heavy chain and TYR35 of the light chain formed a salt bridge and two hydrogen
bonds for specific binding. The key roles of SER52 and ALA97 were further
confirmed by site-directed mutation. A specificity analysis using 14 ofloxacin
analogues indicates that the length of the bond formed between the piperazine
ring and the antibody plays key roles in specific recognition. This work helps
to clarify the mechanisms through which antibodies recognize small molecules and
improve immune detection methods.
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