Cloning, High Level
Expression and Purification of Rat βB2-crystallin
ZHAO Hui-Ren*, HU Shu-Qun, PEI Dong-Sheng, LU Liang, ZHANG
Guang-Yi
(Research Center for Biochemistry and Molecular Biology, Xuzhou Medical
College, Xuzhou 221002, China)
Abstract β-crystallins
are the largest group of lens structural proteins, which are necessary for both
the high refractive index and the transparency of the eye lens, and have been
implicated in various kinds of cataracts. To obtain abundant βB2-crystallin for
the study of the mechanism of their oligomerization, a bacterial expression
system for βB2-crystallin and a rapid method for its purification were
developed. cDNA encoding rat βB2-crystallin was cloned using RT-PCR. After the
induction of recA promoter with nalidixic acid, abundant protein was
produced in E. coli. βB2-crystallin comprised about 30% of the total
bacterial proteins and it is water-soluble. After anion-exchange chromatography
on DEAE cellulose and gel filtration on Sephadex G-100, the protein was obtained
pure as judged by SDS-PAGE. The high level expression and rapid purification of
recombinant βB2-crystallin will facilitate the further study of
structure-function relationship of βB2-crystallin.
Key words βB2-crystallin； expression； purification； E. coli
Received: July 1,
1999 Accepted: August 16, 1999
* Corresponding author: Tel, 86-516-5748423; Fax, 86-516-5748429; e-mail, [email protected]