Recombinant Human HSPH1 protein

Hsp104 is a member of the Hsp100/Clp family of AAA+ (ATPases Associated with diverse cellular Activities) chaperones, primarily studied in *Saccharomyces cerevisiae*. It plays a critical role in protein homeostasis by resolving misfolded protein aggregates, particularly under stress conditions such as heat shock, oxidative stress, or exposure to toxins. Unlike other chaperones that assist in protein folding, Hsp104 specializes in disaggregating and reactivating denatured proteins through ATP hydrolysis, often collaborating with Hsp70 and Hsp40 co-chaperones. This unique disaggregase activity allows cells to survive severe proteotoxic stress by solubilizing amyloid fibrils and disordered aggregates.

Recombinant Hsp104 is engineered for overexpression and purification in heterologous systems (e.g., *E. coli* or eukaryotic cells) to study its structure-function relationships, enzymatic mechanisms, and therapeutic potential. Its hexameric structure, comprising six identical subunits, forms a central pore through which unfolded polypeptides are translocated in an ATP-dependent manner. Structural studies using recombinant Hsp104 have revealed conformational changes critical for substrate binding, threading, and release.

Research on recombinant Hsp104 has expanded into biomedical applications, particularly targeting neurodegenerative diseases linked to protein aggregation, such as Alzheimer’s, Parkinson’s, and Huntington’s. Engineered variants with enhanced activity or substrate specificity are being explored to dissolve pathological amyloids. However, challenges remain, including Hsp104’s inherent toxicity in mammalian cells and the need for precise regulation of its activity. Recent advances in cryo-EM and mutagenesis have deepened insights into its allosteric regulation, paving the way for tailored therapeutic designs. Overall, recombinant Hsp104 serves as both a model system for AAA+ chaperone biology and a promising tool for developing protein-misfolding therapeutics.

**Background of HSPH1 Recombinant Protein**

HSPH1 (Heat Shock Protein Family H Member 1), also known as HSP105. is a member of the heat shock protein 70 (HSP70) family. It functions as a molecular chaperone, playing a critical role in protein homeostasis by assisting in the folding, stabilization, and transport of client proteins, particularly under stress conditions such as elevated temperatures, oxidative stress, or metabolic imbalances. Structurally, HSPH1 contains an N-terminal ATPase domain, a substrate-binding domain, and a C-terminal domain that mediates interactions with co-chaperones and other HSP70 family members. Unlike canonical HSP70s, HSPH1 exhibits lower ATPase activity and may act as a nucleotide exchange factor to regulate HSP70 machinery.

Recombinant HSPH1 protein is engineered through heterologous expression systems (e.g., *E. coli* or mammalian cell lines) to produce a purified, biologically active form for research. Its production typically involves cloning the *HSPH1* gene into expression vectors, followed by induction, lysis, and affinity chromatography purification. Tagging systems (e.g., His-tag) are often employed to facilitate isolation.

Studies leveraging recombinant HSPH1 have illuminated its role in stress adaptation, cancer progression, and neurodegenerative diseases. It is implicated in suppressing protein aggregation in Alzheimer’s and Parkinson’s models, while its overexpression in cancers correlates with chemoresistance and poor prognosis. Researchers also explore HSPH1 as a therapeutic target, investigating inhibitors or modulators to disrupt stress-response pathways in malignancies.

Current challenges include optimizing recombinant HSPH1 solubility and stability *in vitro*, as well as elucidating its structural dynamics and interactions with co-chaperones. Advances in cryo-EM and structural biology are expected to deepen understanding of its mechanistic roles, aiding drug discovery and cellular stress-response research.