title: Effects of low-shear modeled microgravity on the characterization of recombinant β-D-glucuronidase expressed in Pichia pastoris.
abstract: In this study, we used a high-aspect-ratio vessel (HARV), which could model environment of microgravity on ground to investigate for the first time the effects of low-shear modeled microgravity (LSMMG) on the characterization of recombinant β-D-glucuronidase expressed in Pichia pastoris. The β-D-glucuronidase gene (GenBank accession no. EU095019) derived from Penicillium purpurogenum Li-3 encoding β-D-glucuronidase (PGUS) was expressed in P. pastoris GS115 in two different environments of LSMMG and normal gravity (NG). Results manifested that both LSMMG and NG conditions had insignificant effects on temperature and pH activity (optimal temperature and pH were 55 and 5.0 °C, respectively) and characteristic stability of recombinant PGUS. However, the catalytic activity of recombinant PGUS expressed under LSMMG was less affected by metal ions and EDTA as compared with that of NG. Furthermore, K (m) value of the recombinant PGUS expressed under LSMMG was nearly one fifth of that under NG (1.72 vs. 7.72), whereas catalytic efficiency (k (cat)/K (m)) of PGUS expressed under LSMMG (13.55) was 3.7 times higher than that of NG (3.61). The results initially reveal the significant alterations in catalytic properties of recombinant enzyme in response to LSMMG environment and have potential application in bioprocessing and biocatalysis.
authors.affiliation: School of Life Science, Beijing Institute of Technology, South Zhongguancun Street, Haidian District, Beijing, People's Republic of China.
authors.forename: Feng
authors.initials: F
authors.lastname: Qi
authors.forename: DaZhang
authors.initials: D
authors.lastname: Dai
authors.forename: Yanli
authors.initials: Y
authors.lastname: Liu
authors.forename: Imdad
authors.initials: I
authors.lastname: Kaleem
authors.forename: Chun
authors.initials: C
authors.lastname: Li
mesh_terms: D055592:Biophysical Phenomena; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D005966:Glucuronidase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006112:Gravitation; D008954:Models, Biological; D010407:Penicillium / Q000201:enzymology*; D010843:Pichia / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014893:Weightlessness
chemical_list: D005656:Fungal Proteins; D011994:Recombinant Proteins; D005966:Glucuronidase