Chemistry Reference
In-Depth Information
Table 2.1
Different screening approaches in FBDD.
Method
Throughput
a
Type of
information
Structural data
b
Multiplexing of
ligands
NMR
Ligand-based
100s
Direct detection of
binding events
based on chemical
identity of ligand
Yes: epitope map
of ligand
Ye s
[115]
NMR
Target-based
<
10
Direct detection of
binding-induced
changes in target
conformation
Yes: changes in
target, 3D
structure in some
cases
Yes, but difficult
X-ray
crystallography
10s
Interpretation of
electron density
Yes: 3D structure
Yes, but no
isosteres in
mixture
MS
1000s
Direct detection of
binding events
based upon
molecular weight
changes
No
Yes, but MW
must differ
SPR
1000s
Direct detection of
binding events
based upon MW
changes
No
No
ITC
<
10
Indirect changes in
thermodynamic
parameters of
system
Indirect inference
based on
changes in
thermodynamic
parameters
No
Fluorescence
c
10-1000s
Indirect changes in
fluorescence
properties of
ligands or probes
No
No
Biochemical
>
10 000
Direct changes in
functional activity
of target.
No
No
a
Number of compounds that can be routinely screened on a daily basis.
b
Structural data are defined as information on how the ligand binds to the target at an atomic level.
c
Includes all types of assays, including ThermoFluor,
[116−118]
, fluorescence polarization, fluorescence quenching, etc.
will suit all screening needs. Although it is possible to create one diverse fragment library
to be used as a primary library, it is more advisable to have screening libraries with many
different fragment libraries available depending on the results of the assay assessment.
Acompromise between these two extremes is to use 'cascaded' libraries (discussed below).
Screening libraries should be different depending upon a choice of biochemical versus
biophysical screens, e.g. a biophysical library that contains all the fluorescence quenching
fragments in your collection. The restrictions that can be placed upon generic, 'diverse'
libraries based on the result of assay assessment can be onerous and lead to the out-of-hand
removal of fragments that can be of great interest depending on the target of interest.
