Recombinant Lactobacillus johnsonii Elongation factor Ts (tsf)

Introduction

Recombinant Lactobacillus johnsonii Elongation Factor Ts (EF-Ts) is a genetically engineered derivative of the bacterial elongation factor Ts, a critical enzyme in translation machinery. This recombinant form is designed to enhance or alter specific functional properties of the native protein, such as its role in guanine nucleotide exchange or host-microbe interactions. While extensive research has focused on its counterpart, EF-Tu, EF-Ts remains less studied in the context of L. johnsonii. This article synthesizes available data on recombinant EF-Ts, emphasizing its molecular characteristics, functional roles, and potential applications.

Structure and Function of EF-Ts

EF-Ts is a nucleotide exchange factor (NEF) that facilitates the recycling of EF-Tu, a GTP-binding protein essential for delivering aminoacylated tRNA to the ribosome during translation . In L. johnsonii, EF-Ts interacts with EF-Tu to exchange GDP for GTP, enabling ternary complex formation (EF-Tu·GTP·aa-tRNA) . The recombinant version of EF-Ts retains this core function but may include engineered modifications, such as enhanced stability or altered binding affinity, to optimize its activity in specific applications.

Role in Host-Microbe Interactions

While EF-Tu has been extensively studied for its moonlighting roles in adhesion and immune modulation , EF-Ts’s role in host interactions remains underexplored. In L. johnsonii, EF-Tu binds to mucins and intestinal cells in a pH-dependent manner, contributing to gut colonization . Recombinant EF-Ts may indirectly influence these processes by modulating EF-Tu activity, though direct evidence is lacking. Emerging studies suggest that post-translational modifications (e.g., phosphorylation) of EF-Ts in other bacteria regulate its function under stress , potentially influencing host interactions.

Recombinant Engineering and Applications

Recombinant L. johnsonii strains expressing modified EF-Ts are being investigated for probiotic applications, particularly in gut health and immune modulation. For example, recombinant L. johnsonii expressing granulocyte-macrophage colony-stimulating factor (GM-CSF) demonstrated anti-inflammatory effects in bovine endometritis . While EF-Ts itself has not been directly engineered for such purposes, its role in optimizing EF-Tu activity suggests potential for co-expression strategies to enhance therapeutic efficacy.

Research Gaps and Future Directions

Despite its critical role in translation, recombinant EF-Ts in L. johnsonii remains understudied. Key areas for investigation include:

• Moonlighting Functions: Do EF-Ts variants exhibit adhesion or immune-modulatory roles akin to EF-Tu?

• Host-Specific Interactions: How do recombinant EF-Ts modifications alter binding to mucins or epithelial cells?

• Therapeutic Potential: Can engineered EF-Ts enhance the efficacy of probiotic strains in treating infections or inflammatory disorders?