Virologica Sinica

, 24:518

An improved strategy for efficient expression and purification of soluble HIV-1 tat protein in E.coli

Authors

  • Shi-meng Zhang
    • The Department of Radiation Toxicology and OncologyBeijing Institute of Radiation Medicine
  • Rong Fan
    • The Department of Radiation Toxicology and OncologyBeijing Institute of Radiation Medicine
  • Tian-yi Yang
    • The Department of Radiation Toxicology and OncologyBeijing Institute of Radiation Medicine
  • Yi Sun
    • The Department of Radiation Toxicology and OncologyBeijing Institute of Radiation Medicine
  • Jing-yun Li
    • Institute of Microbiology and Epidemiology
  • Qin-zhi Xu
    • The Department of Radiation Toxicology and OncologyBeijing Institute of Radiation Medicine
    • The Department of Radiation Toxicology and OncologyBeijing Institute of Radiation Medicine
Article

DOI: 10.1007/s12250-009-3068-6

Cite this article as:
Zhang, S., Fan, R., Yang, T. et al. Virol. Sin. (2009) 24: 518. doi:10.1007/s12250-009-3068-6

Abstract

Although the endogenous function of Tat has been elucidated in the past twenty years, the study of its exogenous activity has been hampered due to the difficulty of large scale preparation of the active Tat protein. To express the full-length Tat protein in E.coli, the tat gene was cloned from an HIV infected patient by overlapping PCR. Rare codon usage analysis showed that rare E.coli codons, especially consecutive rare codons for Arg, account for 14% (14 of 101) rare E.coli codons in the tat gene. The expression of the HIV-1 tat gene was verified to be very poor in strain BL21 (DE3) due to the abundance of rare codons; however, tat gene expression was found to be very efficient in the host strain of Rosetta-gami B (DE3), which was supplemented with six rare tRNAs for Arg, Leu, Ile and Pro. Subsequent purification revealed that the proteins are soluble and unusually, the tagged Tat can form dimers independent of cystine disulfide bonds. The purity, integrity and molecular weight of the Tat protein were demonstrated by MALDI-TOF mass spectrometry. Reporter gene activating assay was further confirmed by investigating the transactivation activity of the recombinant Tat protein. Our improved strategy for efficient high level expression and purification of soluble Tat protein has paved the way to fully investigate its exogenous function.

Key words

HIVtat geneE.coliProtein expressionCodon usage

CLC number

R373

Copyright information

© Wuhan Institute of Virology, CAS and Springer Berlin Heidelberg 2009