Intramembrane protease RasP boosts protein production in Bacillus
- Jolanda Neef†1,
- Cristina Bongiorni†2,
- Vivianne J. Goosens1, 3,
- Brian Schmidt2 and
- Jan Maarten van Dijl1Email author
© The Author(s) 2017
Received: 30 December 2016
Accepted: 31 March 2017
Published: 4 April 2017
The microbial cell factory Bacillus subtilis is a popular industrial platform for high-level production of secreted technical enzymes. Nonetheless, the effective secretion of particular heterologous enzymes remains challenging. Over the past decades various studies have tackled this problem, and major improvements were achieved by optimizing signal peptides or removing proteases involved in product degradation. On the other hand, serious bottlenecks in the protein export process per se remained enigmatic, especially for protein secretion at commercially significant levels by cells grown to high density. The aim of our present study was to assess the relevance of the intramembrane protease RasP for high-level protein production in B. subtilis.
Deletion of the rasP gene resulted in reduced precursor processing and extracellular levels of the overproduced α-amylases AmyE from B. subtilis and AmyL from Bacillus licheniformis. Further, secretion of the overproduced serine protease BPN’ from Bacillus amyloliquefaciens was severely impaired in the absence of RasP. Importantly, overexpression of rasP resulted in threefold increased production of a serine protease from Bacillus clausii, and 2.5- to 10-fold increased production of an AmyAc α-amylase from Paenibacillus curdlanolyticus, depending on the culture conditions. Of note, growth defects due to overproduction of the two latter enzymes were suppressed by rasP-overexpression.
Here we show that an intramembrane protease, RasP, sets a limit to high-level production of two secreted heterologous enzymes that are difficult to produce in the B. subtilis cell factory. This finding was unexpected and suggests that proteolytic membrane sanitation is key to effective enzyme production in Bacillus.
KeywordsBacillus RasP Site-2 protease Secretion Amylase Protease
Secretory protein production is of critical importance in biotechnology, because this generally delivers high amounts of correctly folded proteins for which downstream processing from the fermentation broth is relatively easy. The Gram-positive bacterium Bacillus subtilis and related bacilli are amongst the best protein producers known today and, therefore, frequently used to produce commercially relevant enzymes. In particular, these organisms are suitable for large-scale high-density fermentation, leading to product yields in the 25 g/l range . Thus, they have a long history in the production of, for example, amylases [2, 3] and proteases [2, 4] used in the food, textile and pharmaceutical industries . Another advantage of B. subtilis and its close relatives is that they lack toxic by-products, such as endotoxin, which makes them suitable for the Qualified Presumption of Safety (QPS) status of the European Food Safety Authority. Accordingly, many Bacillus products have obtained the Generally Recognized As Safe (GRAS) status from the US Food and Drug Administration [6, 7].
Much effort has been made to optimize protein secretion in B. subtilis. Major improvements were achieved by optimizing signal peptides [8, 9] or removing proteases involved in product degradation . For example, the deletion of multiple genes for extracellular proteolytic enzymes allowed efficient production not only of technical enzymes, such as a thermostable β-1,3-1,4-glucanase from Clostridium thermocellum , but also of pharmaceutical proteins, such as single-chain antibodies  or human interleukin-3 . Further improvements in protein secretion were achieved at lab-scale by overexpression of the signal peptidase SipS , the peptidyl-prolyl cis/trans isomerase PrsA , or the staphylococcal thiol-disulphide oxidoreductase DsbA . Nonetheless, serious bottlenecks in the protein export process per se have remained enigmatic, especially for protein secretion at commercially significant levels by cells grown to high density .
Notably, it was previously shown that deleting the gene for the intramembrane protease RasP of B. subtilis led to elevated levels of the membrane proteins FtsL , HtrA and HtrB, but compromised the production of various other membrane proteins  and processing of the α-amylase AmyQ of Bacillus amyloliquefaciens [20, 21]. This focused our attention on a possible role of RasP in secretory protein production, especially because the biogenesis of many membrane proteins relies on the general secretory pathway . RasP belongs to the family of site-2 proteases (S2P), more specifically the zink-metallo proteases, which cleave their substrates within the plane of the cytoplasmic membrane . These proteases are conserved in all domains of life where they have roles in regulated intramembrane proteolysis. For instance, the Escherichia coli S2P named RseP was shown to cleave signal peptides upon their signal peptidase-mediated liberation from secretory precursor proteins [24, 25]. B. subtilis RasP was shown to cleave the anti-sigma factor RsiW under conditions of oxidative- or temperature stress, causing induction of the so-called σW regulon, which is believed to support cell envelope integrity and to mitigate effects of extracellular stress [20, 21, 26, 27]. Therefore, the present study was aimed at determining whether RasP could be a bottleneck for protein production in B. subtilis. Indeed, our results show that RasP overexpression can boost protein production in this important cell factory.
Bacterial strains and growth conditions
Bacterial strains used in this study
Relevant genotypes and phenotypes
Source or reference
B. subtilis strain
degUHy32, amyE::xylRPxylAcomK-ermC, Δupp::neoR, NeoR
degUHy32, amyE::xylRPxylAcomK-ermC, aprE::PaprE-amyL catR Tbpnʹ; EmR; CmR
degUHy32, amyE::xylRPxylAcomK-ermC, aprE::PaprE-amyE catR Tbpnʹ; EmR; CmR
degUHy32, amyE::xylRPxylAcomK-ermC, aprE::PaprE-bpnʹ catR Tbpnʹ; EmR; CmR
degUHy32, amyE::xylRPxylAcomK-ermC, Δupp::neoR, ΔrasP::upp-phleoR-cI EmR; PhleoR; NeoS
degUHy32, amyE::xylRPxylAcomK-ermC, aprE::PaprE-amyL catR, Δupp::neoR, ΔrasP::upp-phleoR-cI catR; EmR; PhleoR; NeoS CmR
degUHy32, ∆scoC, amyE::xylRPxylAcomK-ermC, ∆opp, aprE::PaprE-amyE catR, Δupp::neoR, ΔrasP::upp-phleoR-cI catR; EmR; PhleoR; NeoS CmR
degUHy32, ∆scoC, amyE::xylRPxylAcomK-ermC, ∆opp, aprE::PaprE-bpn’ catR; Δupp::neoR, ΔrasP::upp-phleoR-cI EmR; PhleoR; NeoS CmR
degUHy32, amyE::xylRPxylAcomK-ermC, Δupp::neoR, ΔtepA::upp-phleoR-cI EmR; PhleoR; NeoS
degUHy32, amyE::xylRPxylAcomK-ermC, aprE::PaprE-amyL catR, Δupp::neoR, ΔtepA::upp-phleoR-cI catR; EmR; PhleoR; NeoS CmR
degUHy32, amyE::xylRPxylAcomK-ermC, aprE::PaprE-amyE catR, Δupp::neoR, ΔtepA::upp-phleoR-cI catR; EmR; PhleoR; NeoS CmR
degUHy32, amyE::xylRPxylAcomK-ermC, aprE::PaprE-bpnʹ catR; Δupp::neoR, ΔtepA::upp-phleoR-cI EmR; PhleoR; NeoS CmR
degUHy32, amyE::xylRPxylAcomK-ermC, aprE::PaprE-properase catR Tbpnʹ; EmR; CmR
degUHy32, amyE::xylRPxylAcomK-ermC, aprE::PaprE-properase catR Tbpnʹ, spoIIIAH::PspoVG-rasP; EmR; CmR
degUHy32, amyE::xylRPxylAcomK-ermC, aprE::PaprE-amyAc catR Tbpnʹ; EmR; CmR
degUHy32, amyE::xylRPxylAcomK-ermC, aprE::PaprE-amyAc catR Tbpnʹ, spoIIIAH::PspoVG-rasP; EmR; CmR
Multicopy shuttle vector replicating in E. coli and B. subtilis contains IPTG-inducible Pspac; AmpR, EmR
pHT315-Pspac derivative, EmR is replaced by KmR; AmpR, KmR
pHT315K-Pspac derivative, contains IPTG-inducible rasP; AmpR, KmR
Construction of strains and plasmids
Primers used in this study
5′ → 3′ nucleotide sequence
To complement the ΔrasP mutation, plasmid pHTK315, a derivative of pHT315-Pspac  containing the kan gene for kanamycin resistance was constructed using the CPEC strategy described by Quan et al. . Plasmid pHT315-Pspac was amplified by PCR using the primers pHT315CPEC.fw and pHT315CPEC.rev. In parallel, the kan gene was amplified from the vector pGDL48 , using the primers kanaCPEC.fw and kanaCPEC.rev both containing approximately 30 bp overlap with the pHT315-Pspac vector. The two resulting PCR fragments were fused and amplified by PCR, and the resulting amplicon was used to transform competent cells of E. coli strain TG1. The plasmid thus obtained was named pHTK315. Next, plasmid pHTK315-rasP was constructed following the same strategy. For amplification of pHTK315, the primer combination pHT315rasP.fw/pHT315rasP.rev was used, and rasP was amplified using the primer combinations rasP.fw/rasP.rev. Both fragments were fused by PCR based on the 30 bp overlaps. The resulting amplicon was used to transform competent cells of E. coli TG1, and the plasmid thus obtained was named pHTK315-rasP. The correctness of pHTK315 and pHTK315-rasP was verified by sequencing and, subsequently, these plasmids were introduced into B. subtilis using xylose-induced competence, as described above. After the transformation, mutant strains containing amplified amyE, amyL or bpnʹ expression cassettes were selected by repeated transfers to fresh LB plates containing 25 μg/ml chloramphenicol.
Analysis of secreted protein production by LDS-PAGE
Cultures were inoculated from LB plates with 25 μg/ml chloramphenicol and grown for approximately 8 h in LB broth with 25 µg/ml chloramphenicol. These cultures were diluted 1000-fold in MBU medium with 2.5 µg/ml chloramphenicol in Ultra Yield Flasks™ (Thomson Instrument Company) and incubated for approximately 16 h at 37 °C, 280 rpm in a Multitron orbital shaker (Infors) at high humidity. After measuring and correcting for the optical density at 600 nm (OD600), equal amounts of cells were separated from the culture medium by centrifugation. For the analysis of extracellular proteins, proteins in the culture medium were precipitated with trichloroacetic acid (TCA; 10% w/v final concentration), dissolved in LDS buffer (Life Technologies) and heated for 10 min at 95 °C. Next, proteins were separated by LDS-PAGE on 10% NuPage gels (Life Technologies). Gels were stained with SimplyBlue™ SafeStain (Life Technologies). Gel images were quantified with the ImageJ software (http://imagej.nih.gov/ij/).
Pulse-chase protein labeling experiments
Pulse-chase labeling of B. subtilis proteins was performed using Easy tag [35S]-methionine (PerkinElmer Inc.). Immunoprecipitation and LDS-PAGE were performed as described previously  using the following adaptations. Cells were grown for 16 h in MBU with 2.5 µg/ml chloramphenicol as described before and diluted 1 h prior to the actual labeling to OD600 ~0.7 in fresh MBU with 2.5 µg/ml chloramphenicol. Labeling was performed with 25 µCi [35S]-methionine for 30 s before adding an excess amount of unlabeled methionine (chase; 0.6 mg/ml final concentration). Samples were collected at several time points, followed by direct precipitation of the proteins with 10% TCA (w/v) on ice. Precipitates were re-suspended in lysis buffer (10 mM Tris pH 8, 25 mM MgCl2, 200 mM NaCl and 5 mg/ml lysozyme). After 10–15 min incubation at 37 °C, lysis was achieved by adding 1% (w/v) SDS and heating for 10 min at 100 °C. Specific polyclonal antibodies against AmyE or AmyL were used for immunoprecipitation of the respective labeled proteins in STD-Tris buffer (10 mM Tris pH 8.2, 0.9% (w/v) NaCl, 1.0% (v/v) triton X-100, 0.5% (w/v) sodium deoxycholate) with the help of Protein A affinity medium (Mabselect Sule, GE Healthcare Life Sciences).
Because of the high proteolytic activity of BPNʹ, which also degrades antibodies, the immunoprecipitation of BPNʹ was performed in the presence of a specific serine protease inhibitor (4 mM, Pefablock SC, Roche). Due to aspecific binding of the BPNʹ antibodies to unidentified cellular proteins of B. subtilis, the immunoprecipitation of BPNʹ was only performed to assay secreted BPNʹ in TCA-precipitated culture medium samples. Labeled proteins were separated by LDS-PAGE using 10% NuPage gels (Life Technologies) and visualized using a Cyclon Plus Phosphor Imager (Perkin Elmer). Quantification of the obtained data was achieved by making use of the ImageJ software.
For pulse-chase labeling studies on the complementation of the ΔrasP mutation, cells containing pHTK315-rasP or control cells containing the empty vector pHTK315 were pre-cultured for 20 h in MBU with 2.5 µg/ml chloramphenicol, because these cells grow slightly slower than cells without such plasmids. One hour prior to labeling with [35S]-methionine, the cells were diluted to an OD600 of ~0.7 in fresh MBU with 2.5 µg/ml chloramphenicol containing 25 µM isopropyl β-d-1-thiogalactopyranoside (IPTG) necessary for the induction of the Pspac promoter. The pulse-chase protein labeling was performed as described above.
Assays for Properase or AmyAc production
To analyze Properase secretion by cells overexpressing rasP or wt control cells, the respective strains were pre-cultured for 5 h in LB at 37 °C. From these pre-cultures 1.5 OD units were used to inoculate 25 ml of MBU medium in Ultra Yield Flasks™, and culturing was continued at 37 °C (250 rpm, 70% humidity). Samples were withdrawn from the cultures at 18, 25, 41, 48 and 65 h of growth for OD600 readings and protease activity measurements. OD600 was determined using a SpectraMax spectrophotometer (Molecular Devices, Downington, PA, USA). Protease activity in the samples was determined by incubating sample aliquots with the synthetic substrate N-Succinyl-Ala-Ala-Pro-Phe p-nitroanilide (Sigma Chemical Co) and absorbance readings at 405 nm using a SpectraMax spectrophotometer, as described previously in WO 2010/144283.
To test the effect of rasP overexpression on the production of AmyAc, four colonies from the rasP overexpressing strain or the wt control strain were used to inoculate LB with 25 µg/ml chloramphenicol and the resulting pre-cultures were grown for 4 h at 37 °C. Next, 0.075 OD units from a pre-culture were used to inoculate 2 ml of medium (5SM12 or MBU) in 24 deep well microtiter plates and cultures were grown for 48 h at 37 °C under vigorous shaking. Samples were withdrawn at 18, 25, 41 and 48 h of culturing for OD600 readings and amylase activity measurements. Amylase activity in whole-broth samples was assayed with the Ceralpha HR kit (Megazyme, Wicklow, Ireland) and absorbance readings at 400 nm according to the manufacturer’s instructions.
Results and discussion
In conclusion, our present study shows that the S2P intramembrane protease RasP sets the limit to efficient extracellular production of two proteins in B. subtilis, namely Properase and an AmyAc type amylase. These proteins are difficult to produce, which is partly due to effects on cell growth and/or viability in late stages of the fermentation process. Enhanced expression of rasP can overcome these negative effects, and seems even capable of boosting the secretion of the AmyAc type amylase up to tenfold. Our present findings are unprecedented, giving the first proof-of-principle that overexpression of a protease that cleaves within the plane of the cytoplasmic membrane of a bacterium can lead to improved protein production. The precise mechanism by which RasP exerts this effect in Bacillus is not yet known but, based on knowledge from other studies on S2P proteases, we envisage at least three possible scenarios. Firstly, RasP may facilitate the removal of cleaved signal peptides from the membrane , secondly, RasP may clear the membrane of mislocalized secretory precursor proteins that may interfere with essential membrane processes , or thirdly, overproduced RasP may modulate expression of σw-dependent genes that somehow influence productivity . In these three scenarios, rasP overexpression could increase the fitness of the producing cells through the prevention of membrane and cell envelope perturbations. This would then lead to enhanced growth and productivity. A fourth possible explanation would be that RasP activity precludes potentially inhibitory effects of accumulating signal peptides on the SecA preprotein translocation motor  and/or on signal peptidases that convert translocated precursors of secretory proteins to the mature form . Of course, combinations of these four scenarios are also conceivable. Irrespective of the precise mechanisms, we conclude that RasP can be applied to boost protein secretion in Bacillus, and that the overexpression of this and other S2P proteases represents a promising avenue for future cell factory engineering.
Generally Recognized As Safe
lithium dodecyl sulphate
- OD600 :
optical density at 600 nm
polyacrylamide gel electrophoresis
polymerase chain reaction
Qualified Presumption of Safety
JN, CB, BS and JMvD conceived the study and analyzed the data; JN, CB, VJG and JMvD performed the experiments; and JN, CB and JMvD wrote the paper. All authors read and approved the final manuscript.
JN, VJG and JMvD declare no competing financial interests. CB and BS are employees of DuPont Industrial Biosciences.
Availability of data and materials
All data generated or analyzed during this study are included in this published article.
Consent for publication
The present manuscript has been seen and approved by all authors. They agree with its content and submission to Microbial Cell Factories.
This work was supported by funding from Genencor/Dupont.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
- Van Dijl JM, Hecker M. Bacillus subtilis: from soil bacterium to super-secreting cell factory. Microb Cell Fact. 2013;12(1):3.View ArticleGoogle Scholar
- Sarvas M, Harwood CR, Bron S, Van Dijl JM. Post-translocational folding of secretory proteins in Gram-positive bacteria. Biochim Biophys Acta. 2004;1694:311–27.Google Scholar
- Palva I. Molecular cloning of alpha-amylase gene from Bacillus amyloliquefaciens and its expression in B. subtilis. Gene. 1982;19(1):81–7.View ArticleGoogle Scholar
- Krishnappa L, Dreisbach A, Otto A, Goosens VJ, Cranenburgh R, Harwood CR, Becher D, Van Dijl JM. Extracytoplasmic proteases determining the cleavage and release of secreted proteins, lipoproteins, and membrane proteins in Bacillus subtilis. J Proteome Res. 2013;12:4101–10.View ArticleGoogle Scholar
- Westers L, Westers H, Quax WJ. Bacillus subtilis as cell factory for pharmaceutical proteins: a biotechnological approach to optimize the host organism. Biochim Biophys Acta. 2004;1694:299–310.View ArticleGoogle Scholar
- Olempska-Beer ZS, Merker RI, Ditto MD, DiNovi MJ. Food-processing enzymes from recombinant microorganisms—a review. Regul Toxicol Pharmacol. 2006;45(2):144–58.View ArticleGoogle Scholar
- Earl AM, Losick R, Kolter R. Ecology and genomics of Bacillus subtilis. Trends Microbiol. 2008;16(6):269–75.View ArticleGoogle Scholar
- Brockmeier U, Caspers M, Freudl R, Jockwer A, Noll T, Eggert T. Systematic screening of all signal peptides from Bacillus subtilis: a powerful strategy in optimizing heterologous protein secretion in Gram-positive bacteria. J Mol Biol. 2006;362(3):393–402.View ArticleGoogle Scholar
- Caspers M, Brockmeier U, Degering C, Eggert T, Freudl R. Improvement of Sec-dependent secretion of a heterologous model protein in Bacillus subtilis by saturation mutagenesis of the N-domain of the AmyE signal peptide. Appl Microbiol Biotechnol. 2010;86(6):1877–85.View ArticleGoogle Scholar
- Pohl S, Bhavsar G, Hulme J, Bloor AE, Misirli G, Leckenby MW, Radford DS, Smith W, Wipat A, Williamson ED, Harwood CR, Cranenburgh RM. Proteomic analysis of Bacillus subtilis strains engineered for improved production of heterologous proteins. Proteomics. 2013;13(22):3298–308.View ArticleGoogle Scholar
- Luo Z, Gao Q, Li X, Bao J. Cloning of LicB from Clostridium thermocellum and its efficient secretive expression of thermostable beta-1,3-1,4-glucanase. Appl Biochem Biotechnol. 2014;173(2):562–70.View ArticleGoogle Scholar
- Wu XC, Ng SC, Near RI, Wong SL. Efficient production of a functional single-chain antidigoxin antibody via an engineered Bacillus subtilis expression-secretion system. Biotechnology (N Y). 1993;11(1):71–6.View ArticleGoogle Scholar
- Westers L, Dijkstra DS, Westers H, van Dijl JM, Quax WJ. Secretion of functional human interleukin-3 from Bacillus subtilis. J Biotechnol. 2006;123(2):211–24.View ArticleGoogle Scholar
- Bolhuis A, Sorokin A, Azevedo V, Ehrlich SD, Braun PG, De Jong A, Venema G, Bron S, Van Dijl JM. Bacillus subtilis can modulate its capacity and specificity for protein secretion through temporally controlled expression of the sipS gene for signal peptidase I. Mol Microbiol. 1996;22(4):605–18.View ArticleGoogle Scholar
- Kontinen VP, Sarvas M. The PrsA lipoprotein is essential for protein secretion in Bacillus subtilis and sets a limit for high-level secretion. Mol Microbiol. 1993;8(4):727–37.View ArticleGoogle Scholar
- Kouwen TR, van der Goot A, Dorenbos R, Winter T, Antelmann H, Plaisier MC, Quax WJ, van Dijl JM, Dubois JY. Thiol-disulphide oxidoreductase modules in the low-GC Gram-positive bacteria. Mol Microbiol. 2007;64(4):984–99.View ArticleGoogle Scholar
- Chen J, Fu G, Gai Y, Zheng P, Zhang D, Wen J. Combinatorial Sec pathway analysis for improved heterologous protein secretion in Bacillus subtilis: identification of bottlenecks by systematic gene overexpression. Microb Cell Fact. 2015;14:92. doi:10.1186/s12934-015-0282-9.View ArticleGoogle Scholar
- Bramkamp M, Weston L, Daniel RA, Errington J. Regulated intramembrane proteolysis of FtsL protein and the control of cell division in Bacillus subtilis. Mol Microbiol. 2006;62(2):580–91.View ArticleGoogle Scholar
- Zweers JC, Wiegert T, van Dijl JM. Stress-responsive systems set specific limits to the overproduction of membrane proteins in Bacillus subtilis. Appl Environ Microbiol. 2009;75(23):7356–64.View ArticleGoogle Scholar
- Heinrich J, Hein K, Wiegert T. Two proteolytic modules are involved in regulated intramembrane proteolysis of Bacillus subtilis RsiW. Mol Microbiol. 2009;74(6):1412–26.View ArticleGoogle Scholar
- Heinrich J, Lundén T, Kontinen VP, Wiegert T. The Bacillus subtilis ABC transporter EcsAB influences intramembrane proteolysis through RasP. Microbiology. 2008;154:1989–97.View ArticleGoogle Scholar
- Yuan J, Zweers JC, van Dijl JM, Dalbey RE. Protein transport across and into cell membranes in bacteria and archaea. Cell Mol Life Sci. 2010;67(2):179–99.View ArticleGoogle Scholar
- Dalbey RE, Wang P, van Dijl JM. Membrane proteases in the bacterial protein secretion and quality control pathway. Microbiol Mol Biol Rev. 2012;76(2):311–30.View ArticleGoogle Scholar
- Akiyama Y, Kanehara K, Ito K. RseP (YaeL), an Escherichia coli RIP protease, cleaves transmembrane sequences. EMBO J. 2004;23:4434–42.View ArticleGoogle Scholar
- Saito A, Hizukuri Y, Matsuo E, Chiba S, Mori H, Nishimura O, Ito K, Akiyama Y. Post-liberation cleavage of signal peptides is catalyzed by the site-2 protease (S2P) in bacteria. Proc Natl Acad Sci USA. 2011;108(33):13740–5.View ArticleGoogle Scholar
- Zweers JC, Nicolas P, Wiegert T, Van Dijl JM, Denham EL. Definition of the σ (W) regulon of Bacillus subtilis in the absence of stress. PLoS ONE. 2012;7(11):e48471.View ArticleGoogle Scholar
- Helmann JD. Bacillus subtilis extracytoplasmic function (ECF) sigma factors and defense of the cell envelope. Curr Opin Microbiol. 2016;30:122–32.View ArticleGoogle Scholar
- Vogtentanz G, Collier KD, Bodo M, Chang JH, Day AG, Estell DA, Falcon BC, Ganshaw G, Jarnagin AS, Kellis JT Jr, Kolkman MA, Lai CS, Meneses R, Miller JV, de Nobel H, Power S, Weyler W, Wong DL, Schmidt BF. A Bacillus subtilis fusion protein system to produce soybean Bowman–Birk protease inhibitor. Protein Expr Purif. 2007;55(1):40–52.View ArticleGoogle Scholar
- Fabret C, Ehrlich SD, Noirot P. A new mutation delivery system for genome-scale approaches in Bacillus subtilis. Mol Microbiol. 2002;46(1):25–36.View ArticleGoogle Scholar
- Yang M, Galizzi A, Henner D. Nucleotide sequence of the amylase gene from Bacillus subtilis. Nucleic Acids Res. 1983;11(2):237–49.View ArticleGoogle Scholar
- Yuuki T, Nomura T, Tezuka H, Tsuboi A, Yamagata H, Tsukagoshi N, Udaka S. Complete nucleotide sequence of a gene coding for heat- and pH-stable alpha-amylase of Bacillus licheniformis: comparison of the amino acid sequences of three bacterial liquefying alpha-amylases deduced from the DNA sequences. J Biochem. 1985;98(5):1147–56.View ArticleGoogle Scholar
- Wells JA, Ferrari E, Henner DJ, Estell DA, Chen EY. Cloning, sequencing, and secretion of Bacillus amyloliquefaciens subtilisin in Bacillus subtilis. Nucleic Acids Res. 1983;11(22):7911–25.View ArticleGoogle Scholar
- Wells JA, Cunningham BC, Graycar TP, Estell DA. Recruitment of substrate-specificity properties from one enzyme into a related one by protein engineering. Proc Natl Acad Sci USA. 1987;84(15):5167–71.View ArticleGoogle Scholar
- Valle F, Ferrari E. Subtilisin: a redundantly temporally regulated gene. In: Smith I, Slepecky AR, Selow P, editors. Regulation of prokaryotic development. Washington: American Society for Microbiology; 1989. p. 131–46.Google Scholar
- Perego M. Integrational vectors for genetic manipulation in Bacillus subtilis. In: Sonenshein AL, Hoch JA, Losick R, editors. Bacillus subtilis and other Gram-positive bacteria: biochemistry, physiology, and molecular genetics. Washington: American Society for Microbiology; 1993. p. 615–24.Google Scholar
- Fukushima T, Furihata I, Emmins R, Daniel RA, Hoch JA, Szurmant H. A role for the essential YycG sensor histidine kinase in sensing cell division. Mol Microbiol. 2011;79(2):503–22.View ArticleGoogle Scholar
- Quan J, Tian J. Circular polymerase extension cloning of complex gene libraries and pathways. PLoS ONE. 2009;4(7):e6441.View ArticleGoogle Scholar
- Meijer WJ, de Jong A, Bea G, Wisman A, Tjalsma H, Venema G, Bron S, van Dijl JM. The endogenous Bacillus subtilis (natto) plasmids pTA1015 and pTA1040 contain signal peptidase-encoding genes: identification of a new structural module on cryptic plasmids. Mol Microbiol. 1995;17(4):621–31.View ArticleGoogle Scholar
- Van Dijl JM, De Jong A, Smith H, Bron S, Venema G. Non-functional expression of Escherichia coli signal peptidase I in Bacillus subtilis. J Gen Microbiol. 1991;137:2073–83.View ArticleGoogle Scholar
- Ferrari E, Valle F. Mutant aprE promoter. Genencor. 2000; EP1244794 B1.
- Bolhuis A, Matzen A, Hyyryläinen HL, Kontinen VP, Meima R, Chapuis J, Venema G, Van Dijl JM. Singal peptide peptidase- and ClpP-like proteins of Bacillus subtilis required for efficient translocation and processing of secretory proteins. J Biol Chem. 1999;274(35):24585–92.View ArticleGoogle Scholar
- Cunningham K, Wickner W. Specific recognition of the leader region of precursor proteins is required for the activation of translocation ATPase of Escherichia coli. Proc Natl Acad Sci USA. 1989;86:8630–4.View ArticleGoogle Scholar
- Wickner W, Moore K, Dibb N, Geissert D, Rice M. Inhibition of purified Escherichia coli leader peptidase by the leader (signal) peptide of bacteriophage M13 procoat. J Bacteriol. 1987;169:3821–2.View ArticleGoogle Scholar
- Worner K, Szurmant H, Chiang C, Hoch JA. Phosphorylation and functional analysis of the sporulation initiation factor Spo0A from Clostridium botulinum. Mol Microbiol. 2006;59(3):1000–12.View ArticleGoogle Scholar