Methodology article

Construction of a series of vectors for high throughput cloning and expression screening of membrane proteins from Mycobacterium tuberculosis

Huajun Qin^1,2 , Jian Hu^1,2 , Yuanzhi Hua³ , Shridhar V Challa¹ , Timothy A Cross^1,2,4 and Fei P Gao^1,2

¹Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32310, USA

²National High Magnetic Field Laboratory, Tallahassee, Florida 32306, USA

³Scripps Research Institute, La Jolla, California 92037, USA

⁴Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306, USA

author email corresponding author email

BMC Biotechnology 2008, 8:51doi:10.1186/1472-6750-8-51

Published:	16 May 2008

Abstract

Background

One of the major challenges for membrane protein structural genomics is establishing high-throughput cloning and expression screening methods to obtain enough purified protein in a homogeneous preparation for structural and functional studies. Here a series of ligation independent cloning based vectors were constructed to address this challenge.

Results

The feasibility of these vectors was tested with 41 putative membrane proteins from Mycobacterium tuberculosis. The efficiency for direct cloning of these target genes from PCR products was 95% (39/41). Over 40% of cloned genes were overexpressed in Escherichia coli BL21 (DE3)-RP codon plus strain in the first round of expression screening. For those proteins which showed no expression, three protein fusion partners were prepared and it was found that each of the target proteins could be overexpressed by at least one of these fusions, resulting in the overexpression of two thirds of the cloned genes.

Conclusion

This expression platform features high throughput cloning, high flexibility for different constructs, and high efficiency for membrane protein overexpression, and is expected to be useful in membrane protein structural and functional studies.