Design And Synthesis Of Bioaffinity Probe Molecules Containing Boronic Acid Groups

Compounds derive from natural sources with potent biological activity is an important source of active lead compounds.In the development of new drugs,the discovery of active lead compounds is only a prerequisite,and the key step is determining the target.Identifying the target of active compound can not only assist further optimization of the structure,but also help to comfirm the mechanism of this compound in vivo.Therefore,it is of great significance to design a probe molecule and capture the target protein in its natural state.Generally,the active small molecule probe is a method in which an active compound and a reporter group such as biotin are linked through a linking group of a certain length.Co-incubation with cells or cell lysates,after binding of the probe to the target protein,the target protein is purified and enriched by separating the probe from the solution using magnetic beads bound to streptavidin.In this work,to investigate the effects of introducing a boronic acid affinity group into the probe on the affinity between the probe and the target protein,cysteine was used as the center of skeleton,and reporter groups were assembled thereon,respectively.Five different bioaffinity probe molecules were synthesized by the active group and different affinity groups.Firstly,cysteine was chosen as the center of skeleton,and a biotin moiety as a reporter group was assembled by an amidation reaction and a click reaction.Then,four probes with different functions were synthesized by amidation reaction by attaching a benzene ring group,a para-phenylboronic acid group,a meta-phenylboronic acid group and a photoaffinity group benzophenone to the side chain amino group.They were used to compare the different capabilities between the affinity probe molecule containing a boronic acid group and the photoaffinity probe molecule to bind a target protein.Meanwhile,3-mercaptopropionic acid was chosen as the center of skeleton to synthesize a probe functional group with no side chain affinity group was as a blank control.In addition,a high-yield synthesis route of the active moiety has been explored and optimized.The active moiety could be obtained by introducing bromomaleimide group into the structure of novobiocin through nucleophilic substitution reaction and amideation reaction.Finally,five different affinity probes 20 a,20b,20 c,20d and 20 e were synthesized by the 1,4 Michael addition between the thiol group and the maleimide to assemble the reactive group with the functional group of the probe.Those probes will be used in subsequent studies to explore the role of boric acid groups as an affinity auxiliary group in catching target proteins.