E. coli Exonuclease I (Exo I)

Product Introduction

Exo I (Exonuclease I) is a magnesium-dependent exonuclease derived from Escherichia coli that plays a fundamental role in molecular biology research. This enzyme consists of 475 amino acids with a molecular weight of approximately 54.5 kDa. Its three-dimensional structure presents a unique "C"-shaped conformation comprising three main domains: an N-terminal exonuclease active domain, an SH3 domain, and a C-terminal α-helical domain. The active center is located within a positively charged groove, enabling specific recognition and stable binding of single-stranded DNA (ssDNA) substrates, providing the structural basis for efficient catalysis.

Product Specifications

Product Specifications

Application Scenarios

PCR Product Purification and Pre-Sequencing Treatment: Exo I is widely used to remove residual primers from PCR reactions. Leveraging its specific degradation of ssDNA, it efficiently eliminates unbound primers (containing 3'-hydroxyl termini), improving the quality of sequencing templates. This method is particularly critical in next-generation and third-generation sequencing technologies.

Molecular Diagnostics and Biosensors: Exo I is utilized in electrochemical biosensors for signal amplification. For example, when combined with nucleic acid aptamers and nano-silver probes, Exo I-mediated cyclic cleavage of ssDNA significantly enhances the detection sensitivity for target molecules (e.g., tumor markers). This technology offers the advantages of being label-free and having high stability.

References

Breyer WA, et al. (2000). Structure of Escherichia coli exonuclease I suggests how processivity is achieved. Nature Structural Biology. 7(12):1125-1128.