Adaptation of the binding domain of Lactobacillus acidophilus S-layer protein as a molecular tag for affinity chromatography development

Abstract

The SLAPTAG is a novel molecular TAG derived from a protein domain present in the sequence of 22 Lactobacillus acidophilus SlpA (SlpA284-444). Proteins from different biological sources, with different 23 molecular weights or biochemical functions, can be fused in frame to the SLAPTAG and efficiently purified 24 by the specific binding to a bacterial-derived chromatographic matrix named here Bio-Matrix (BM). 25 Different binding and elution conditions were evaluated to set an optimized protocol for the SLAPTAG-26 based affinity chromatography (SAC). The binding equilibrium between SLAPTAG and BM was reached after 27 a few minutes at 4oC, being the apparent dissociation constant (KD) of 4.3 μM, a value which is similar to 28 different Kd determined for other S-layer proteins and their respective bacterial cell walls.