Tomato leaf curl Kerala virus (ToLCKeV) AC3 protein forms a higher order oligomer and enhances ATPase activity of replication initiator protein (Rep/AC1)

Kalyan K Pasumarthy,Sunil K Mukherjee,Nirupam R Choudhury

doi:10.1186/1743-422x-7-128

Kalyan K Pasumarthy, Sunil K Mukherjee + Show 1 more

Open Access

https://doi.org/10.1186/1743-422x-7-128

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Abstract

BackgroundGeminiviruses are emerging plant viruses that infect a wide variety of vegetable crops, ornamental plants and cereal crops. They undergo recombination during co-infections by different species of geminiviruses and give rise to more virulent species. Antiviral strategies targeting a broad range of viruses necessitate a detailed understanding of the basic biology of the viruses. ToLCKeV, a virus prevalent in the tomato crop of Kerala state of India and a member of genus Begomovirus has been used as a model system in this study.ResultsAC3 is a geminiviral protein conserved across all the begomoviral species and is postulated to enhance viral DNA replication. In this work we have successfully expressed and purified the AC3 fusion proteins from E. coli. We demonstrated the higher order oligomerization of AC3 using sucrose gradient ultra-centrifugation and gel-filtration experiments. In addition we also established that ToLCKeV AC3 protein interacted with cognate AC1 protein and enhanced the AC1-mediated ATPase activity in vitro.ConclusionsHighly hydrophobic viral protein AC3 can be purified as a fusion protein with either MBP or GST. The purification method of AC3 protein improves scope for the biochemical characterization of the viral protein. The enhancement of AC1-mediated ATPase activity might lead to increased viral DNA replication.

Highlights

Geminiviruses are emerging plant viruses that infect a wide variety of vegetable crops, ornamental plants and cereal crops
Tomato leaf curl disease (ToLCD) is a cause of concern for the tomato plant. This disease is mostly caused by leaf curl viruses of Geminiviridae family that include more than 50 species of Tomato leaf curl viruses of genus Begomovirus
To better understand the biochemical characteristics of the AC3 protein, we have developed a robust prokaryotic expression system for Tomato leaf curl Kerala virus[India:Kerala II:2005] (ToLCKeV; DQ852623) AC3 protein in E. coli and studied its oligomeric properties in solution

Summary

Introduction

Geminiviruses are emerging plant viruses that infect a wide variety of vegetable crops, ornamental plants and cereal crops. They undergo recombination during co-infections by different species of geminiviruses and give rise to more virulent species. Tomato leaf curl disease (ToLCD) is a cause of concern for the tomato plant. This disease is mostly caused by leaf curl viruses of Geminiviridae family that include more than 50 species of Tomato leaf curl viruses of genus Begomovirus. Threat to the tomato crop is further aggravated by the high level of recombination observed in the geminiviruses during mixed infection resulting in the emergence of new and virulent viral species.

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