Screening a natural product-based combinatorial library using FTICR mass spectrometry

This manuscript reports the use of Fourier transform ion cyclotron resonance mass spectrometry to screen a combinatorially generated natural product-based library for binding affinity to bovine carbonic anhydrase II (bCAII). The fungal natural product 3-chloro-4-hydroxyphenylacetamide was the library template, with 11 secondary amide analogues of this template constituting the combinatorial library. 2-(3-Chloro-4-hydroxyphenyl)-N-(4-sulfamoylphenethyl)acetamide (compound 11) of this library was identified as a tight binding inhibitor of bCAII, by detection of a noncovalent complex corresponding to [bCAII + 11] in the mass spectrum. A competitive bCAII enzyme binding assay validated the mass spectrometry screening result. The equilibrium dissociation constant (Ki) for 11 was measured as 77.4 nM. Preliminary structure–activity investigations of the bioactive natural product analogue are also reported.

FTICR mass spectrometry was utilised to screen a natural product-based combinatorial library for bovine carbonic anhydrase II binders. One high-affinity ligand was identified in a single mass spectrometry experiment and this result was validated by a competitive bCAII enzyme binding assay.Figure optionsDownload as PowerPoint slide