Journal Article

FZJ-2018-00271

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Contribution of single amino acid and codon substitutions to the production and secretion of a lipase by Bacillus subtilis

Skoczinski, P. (First author) ; Volkenborn, K. ; Fulton, A. ; Bhadauriya, A. ; Nutschel, C. ; Gohlke, H.FZJ* ; Knapp, A.FZJ* ; Jaeger, K.-E. (Corresponding author)FZJ*

2017
Biomed Central London

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Please use a persistent id in citations: http://hdl.handle.net/2128/16475  doi:10.1186/s12934-017-0772-z

Abstract: Background: Bacillus subtilis produces and secretes proteins in amounts of up to 20 g/l under optimal conditions. However, protein production can be challenging if transcription and cotranslational secretion are negatively affected, or the target protein is degraded by extracellular proteases. This study aims at elucidating the influence of a target protein on its own production by a systematic mutational analysis of the homologous B. subtilis model protein lipase A (LipA). We have covered the full natural diversity of single amino acid substitutions at 155 positions of LipA by site saturation mutagenesis excluding only highly conserved residues and qualitatively and quantitatively screened about 30,000 clones for extracellular LipA production. Identified variants with beneficial effects on production were sequenced and analyzed regarding B. subtilis growth behavior, extracellular lipase activity and amount as well as changes in lipase transcript levels. Results: In total, 26 LipA variants were identified showing an up to twofold increase in either amount or activity of extracellular lipase. These variants harbor single amino acid or codon substitutions that did not substantially affect B. subtilis growth. Subsequent exemplary combination of beneficial single amino acid substitutions revealed an additive effect solely at the level of extracellular lipase amount; however, lipase amount and activity could not be increased simultaneously. Conclusions: Single amino acid and codon substitutions can affect LipA secretion and production by B. subtilis. Several codon-related effects were observed that either enhance lipA transcription or promote a more efficient folding of LipA. Single amino acid substitutions could improve LipA production by increasing its secretion or stability in the culture supernatant. Our findings indicate that optimization of the expression system is not sufficient for efficient protein production in B. subtilis. The sequence of the target protein should also be considered as an optimization target for successful protein production. Our results further suggest that variants with improved properties might be identified much faster and easier if mutagenesis is prioritized towards elements that contribute to enzymatic activity or structural integrity.

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Contributing Institute(s):

1. Jülich Supercomputing Center (JSC)
2. John von Neumann - Institut für Computing (NIC)
3. Strukturbiochemie (ICS-6)
4. Biotechnologie (IBG-1)
5. Institut für Molekulare Enzymtechnologie (HHUD) (IMET)

Research Program(s):

1. 581 - Biotechnology (POF3-581) (POF3-581)
2. 574 - Theory, modelling and simulation (POF3-574) (POF3-574)
3. 511 - Computational Science and Mathematical Methods (POF3-511) (POF3-511)
4. BioSC - Bioeconomy Science Center (BioSC) (BioSC)

Appears in the scientific report 2017

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Database coverage:
; ; ; ; BIOSIS Previews ; DOAJ Seal ; Ebsco Academic Search ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; SCOPUS ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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