Improvement of extracellular production of a thermophilic subtilase expressed in Escherichia coli by random mutagenesis of its N-terminal propeptide.
Limited secretion capacity remains a drawback of using Escherichia coli as the host for the production of recombinant proteins. In this report, random mutagenesis was performed within the N-terminal propeptide of thermostable WF146 protease, a subtilase from thermophilic Bacillus sp. WF146, generating a variant named WBM(MT) with improved capacity for extracellular production when expressed in E. coli. Two mutations, L(-57)Q and E(-10)D, were identified within the N-terminal propeptide. The amount of WBM(MT) in the culture medium was found to be about three times higher than that of wild type. Besides, the introduction of mutations L(-57)Q/E(-10)D into the N-terminal propeptide also accelerated the maturation of the enzyme. Biochemical analysis indicated that the thermostability and the catalytic activity of mature WBM(MT) were similar to those of wild type. Far-UV CD spectra analysis and limited proteolysis experiments suggested that the mutations L(-57)Q/E(-10)D resulted in a structural change in the N-terminal propeptide of the proform, and the N-terminal propeptide became more flexible, which might be beneficial for the proform to keep in a translocation-competent state. Our result indicates that N-terminal propeptide engineering may be a valuable approach for improving extracellular production of recombinant subtilases expressed in E. coli.
Fang
Nan
N
State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
Zhong
Chuan-Qi
CQ
Liang
Xiaoliang
X
Tang
Xiao-Feng
XF
Tang
Bing
B
D000595:Amino Acid Sequence; D001407:Bacillus / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D005110:Extracellular Space / Q000201:enzymology; D006358:Hot Temperature; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009154:Mutation; D015202:Protein Engineering; D017510:Protein Folding; D011498:Protein Precursors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D012697:Serine Endopeptidases / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D011498:Protein Precursors; D011994:Recombinant Proteins; D012697:Serine Endopeptidases