대장균에서의 T7 발현체계에 의하여 과잉생산된 클로람페니콜 아세틸전이효소와 베타-락타메이즈의 수용성과 활성

Solubilities and Activities of Chloramphenicol Acetyltransferase and $\beta$-Lactamase Overproduced by the T7 Expression System in Escherichia coli

  • 발행 : 1993.08.01

초록

단백질이 어떻게 비수용성이 되는지를 알기위해, 클로람페니콜 아세틸전이효소와 베타-락타메이즈를 과잉생산하여 그들의 수용성과 활성을 측정하였다. 클로람페니콜 아세틸전이효소는 총단백질의 9에서 45%를 차지하였으며, inclusion body 형성없이 완전히 수용성이었으며, 효소활성은 만들어진 양과 비례하였다. 또한 30℃에서 T7 발현체계에 의해 생성된 베타-락타메이즈는 수용성의 숙성체였으나, 37℃에서는 비수용성이 되었다. 세포질에 있는 대부분의 베타-락타메이즈는 비수용성이었고. 페리플라즘 공간에서는 대부분이 수용성이었다. 단백질의 올바른 폴딩을 도와주는 chaperone의 일종인 GroEL 단백질은 본 실험조선에서는 베타-락타베이즈의 수용성을 별로 높이지는 못했다. 세포 내에서 inclusion body의 형성은 단백질의 높은 종도보다는 각각 단밸질 자체의 특성과 관련된 듯하다.

Overproduced proteins in many cases result in forming insoluble inclusion bodies, and their formation might be due to high concentration of protein. To investigate how proteins become insoluble, chloramphenicol acetyltransferase (CAT) and .betha.-lactamase were overproduced, and their solubilities and activities were determined. CAT was accumulated from 9 to 45% of total cellular protein in a fully soluble form without inclusion body formation. CAT specific activity was shown to be proportional to the amount of the protein produced. Moderately produced .betha.-lactamase by the phase T7 expression system at 30.deg.C comprised only mature forms in a soluble form. However, overproduced .betha.-lactamase at 37.deg.C became insoluble. Most precursor forms of .betha.-lactamase in the cytoplasm were insoluble, whereas majority of the mature forms in the periplasm space were soluble. Also, chaperone GroE proteins which assist proper protein folding and translocation did not increase .betha.-lactamase solubility significantly under the experimental condition. It seems that the formation of inclusion bodies in the cell is related to the nature of protein itself rather than just to high concentration of protein.

키워드

참고문헌

  1. Bio/Technology v.10 Dnak-mediated alterations in human growth hormone protein inclusion bodies Blum,P.;M.Velligan;N.Lin;A.Matin
  2. Nature v.336 Transient association of newly synthesized unfolded proteins with the heat-shock GroEL protein Bochkareva,E.S.;N.M.Lissin;A.S.Girchovich
  3. J. Biol. Chem. v.265 Folding and aggregation of β-lactamase in the periplasmic space of Esherichia coli Bowden,G.A.;G.Georgiou
  4. Biochemistry v.30 GroE facilitase refolding of citrate synthase by suppressing aggregation Buchner,J.;M.Schimidt;T.Kiefhaber
  5. Nature v.337 GroE heat-shock proteins promote assembly of foreign prokaryotic ribulose bisphosphate carbozylase oligomers in Escherichia coli Goloubinoff,P.;A.A.Gateby;G.H.Lorimer
  6. J. Bacteriol. v.170 ompT encodes the E. coli outer membrane protease that cleaves T7 RNA polymerase during purification Grodberg,J.;J.J.Dunn
  7. Kor. J. Microbiol. v.27 Selective overproduction of chloramphenicol acetyltransferase in the T7 expression system Kim,H.B.;C.Kang
  8. EMBO J. v.8 Effects of mutation in heat shock genes groES and groEL on protein export in E. coli Kusukawa,N.;T.Yura;K.Ito
  9. J. Bacteriol. v.165 Precursor for elongation factor Tu from E. coli Lifson,E.R.;L.Lindahl;J.M.Zengel
  10. Biochem. J. v.240 The purification of eukaryotic polypeptides synthesized in E. coli Marston,F.A.O.
  11. Anal. Biochem. v.116 Minimization of variation in the response to different proteins of Coomassie blue G dye-binding assay for protein Read,S.M.;D.H.Northcate
  12. Cell v.59 Polypeptide chain binding proteins: catalysis of protein folding and related processes in cells Rothman,J.E.
  13. Methods Enzymol. v.43 Chloramphenicol acetyltransferase from chloramphenicol-resistant bacteria Shaw,W.V.
  14. J. Biol. Chem. v.259 Purification and properties of thiol β-lactamase Sigal,I.S.;W.F.DeGrado;B.J.Thomas;S.R.Petteway,Jr.
  15. J. Mol. Biol. v.189 Use of T7 RNA polymerase to direct selective high-level expression of cloned genes Studier,F.W.;B.A.Moffatt
  16. Methods Enzymol. v.185 Use of T7 RNA polymerase to direct expression of cloned genes Studier,F.W.;A.H.Rosenberg;J.J.Dunn;J.W.Dubendorff