Recombinant Human flgM protein

FlgM is a regulatory protein involved in the flagellar biosynthesis pathway of bacteria, particularly studied in *Salmonella enterica* and other motile Gram-negative species. It functions as an anti-sigma factor that tightly controls the expression of flagellar genes by directly binding to the sigma factor σ28 (FliA), a transcriptional activator required for late-stage flagellar assembly. Under normal conditions, FlgM inhibits σ28 activity, preventing the transcription of genes encoding flagellar hook and filament components. However, as the flagellar basal body matures, FlgM is secreted through the nascent structure, relieving its inhibition on σ28 and allowing the completion of flagellum synthesis. This checkpoint mechanism ensures sequential gene expression, coupling flagellar assembly to bacterial motility and environmental adaptation.

Recombinant FlgM protein is commonly produced in *Escherichia coli* via genetic engineering for structural and functional studies. Its small size (~10 kDa) and solubility properties make it amenable to purification using affinity chromatography, often with tags like His-tag for ease of isolation. Research on recombinant FlgM has provided insights into bacterial gene regulation, protein secretion, and host-pathogen interactions. Studies also explore its role in bacterial stress responses and biofilm formation. Additionally, FlgM serves as a model protein for understanding anti-sigma factor dynamics and has potential applications in developing anti-infective strategies targeting bacterial motility. Structural analyses, including NMR and X-ray crystallography, reveal its N-terminal disordered region and C-terminal σ28-binding domain, highlighting mechanisms of molecular recognition and regulatory flexibility.