Characterization of the overexpressed recombinant human α11 integrin I domain in Escherichia coli for functional analysis

Integrins are crucial adhesion receptors involved in cell-matrix and cell-cell interactions. Integrin α11β1 has been linked to tumor progression, metastasis, angiogenesis, fibrotic diseases, and wound healing. The I domain of integrin α11 plays a vital role in ligand binding, integrin activation, and cell signaling. In this study, we focused on expressing the I domain of integrin α11 in E. coli C41 (DE3) using lysis buffers like Triton X-100, sarkosyl, and urea. We also examined the effect of osmolytes on protein stability. A solid-phase assay assessed the binding of the recombinant I domain to type I collagen. Our findings showed that expression condition changes did not affect the I domain's solubility. We successfully obtained a soluble I domain using sarkosyl lysis buffer and purified it via nickel affinity chromatography, optimizing its stability with 40 mM mannitol. The binding of the I domain to type I collagen is concentration-dependent. This study outlines a method for expressing, purifying, and stabilizing the recombinant I domain of integrin α11, which may facilitate further investigations into this protein.