Call us toll-free

Quick academic help

Don't let the stress of school get you down! Have your essay written by a professional writer before the deadline arrives.

Calculate the price


275 Words


Cholesterol Biosynthesis | Sigma-Aldrich

The bottom portion of mevalonate pathway of E. faecium VTCC-B-935 isolated in Vietnam was introduced into a engineered carotenogenic E. coli resulted in improvement of β-carotene biosynthesis. The pRSET-A expression vector performed better than pET22b(+). Addition of glycerol as carbon source enhanced E. coli cell growth and biosynthesis of β-carotene almost 3 folds.

HMG-CoA is then converted to mevalonate by HMG-CoA reductase (HMGR)

pR-IEIBY contains β-carotene biosynthesis genes and idi. pET28-K1K2D contains genes encoding enzymes catalyze reactions from mevalonate to IPP.

Bile Acid Synthesis, Metabolism and Biological Functions

Where, pR-EIBY and pET22-IEIBY are pRSET-A and pET22b(+) containing multicistronic operon of five genes including idi from E. coli DH5α, crtE, crtI, crtB, and crtY from Pantoea ananatis, respectively. These two vector were used for biosynthesis of β-carotene in recombinant E. coli BL21(DE3). pET28-K1K2D is pET28a(+) containing multicistronic operon of three genes including mvaK1, mvaK2, and mvaD from Enterococcus faecium VTCC-B-935. This vector was used for conversion of mevalonate to IPP. Major component of the vectors and restriction sites used in the construction were indicated. Vector maps were drawn using Vector NTI software version 11.5.1.

In this case report, we first examine the difference of expression vector backbones. In our previous study, three genes including crtE, crtB, and crtI were cloned from Pantoea ananatis for lycopene biosynthesis, and idi was cloned from E. coli for better balancing of IPP [7]. These four genes, together with crtY, were introduced into pRSET-A and pET22b(+) resulted in multicistronic operon vectors pR-IEIBY and pET22-iEIBY, respectively. Secondly, differ from other previous publications, another source of genes encode for the bottom mevalonate pathway enzymes including mvaK1, mvaK2, and mvaD were cloned from Enterococcus faecium VTCC- B-935 isolated in Vietnam and introduced into pET28 vector forming pET28-mvaK1K2D. Subsequently, this vector was transformed into a recombinant E. coli strain which has already contained another expression vector pR-IEIBY. Finally, four additional carbon sources were investigated for higher production of β-carotene using our recombinant system.

Bile Acid Synthesis and Utilization

Biosynthesis partway of β-carotene is indicated in Figure 1. DMAPP and IPP, the building blocks of carotenoid are synthesized via 2-C-methyl-d-erythritol-4-phosphate (MEP) pathway which is autonomous in our chosen host E. coli. However, in theory the natural yield of these precursors is only sufficient for natural need of E. coli in normal growth conditions which is far less than that required once the organism is used as a microbial factory to produce β-carotene. To address this issue, addition of the exogenous mevalonate (MVA) pathway was shown as a reasonable strategy [6,12,18,20,21]. The MVA pathway is divided into two portions, the upper (from acetyl-CoA to MVA) and the lower (from MVA to DMAPP and IPP).
Natural E. coli harbors MEP pathway that enable biosynthesis of FPP from G3P and pyruvate, as well as IPP isomerase catalyze the two-way conversion of IPP and DMAPP, the precursors of carotenoid (yellow part). These precursors could also be synthesized by the mevalonate pathway which is exogenous to E. coli. In this design, the bottom portion of MVA pathway from mevalonate to IPP was recruited from E. faecium VTCC-B-935 isolated in Vietnam (green part). IPP is subsequently used as building blocks for the process of β-carotene synthesis including four steps catalyzed by exogenous crt genes derived from P. ananatis. For better balancing between the two isoforms IPP and DMAPP, in addition to the endogenous idi gene positioned in the genome of E. coli host, another copy of this gene was introduced into the carotenogenic vector for co-over expression with crt genes (blue part).

Order now

    As soon as we have completed your work, it will be proofread and given a thorough scan for plagiarism.


    Our clients' personal information is kept confidential, so rest assured that no one will find out about our cooperation.


    We write everything from scratch. You'll be sure to receive a plagiarism-free paper every time you place an order.


    We will complete your paper on time, giving you total peace of mind with every assignment you entrust us with.


    Want something changed in your paper? Request as many revisions as you want until you're completely satisfied with the outcome.

  • 24/7 SUPPORT

    We're always here to help you solve any possible issue. Feel free to give us a call or write a message in chat.

Order now
  • You submit your order instructions

  • We assign an appropriate expert

  • The expert takes care of your task

  • We send it to you upon completion

Order now
  • 37 684

    Delivered orders

  • 763

    Professional writers

  • 311

    Writers online

  • 4.8/5

    Average quality score

Order now
  • Kim

    "I have always been impressed by the quick turnaround and your thoroughness. Easily the most professional essay writing service on the web."

  • Paul

    "Your assistance and the first class service is much appreciated. My essay reads so well and without your help I'm sure I would have been marked down again on grammar and syntax."

  • Ellen

    "Thanks again for your excellent work with my assignments. No doubts you're true experts at what you do and very approachable."

  • Joyce

    "Very professional, cheap and friendly service. Thanks for writing two important essays for me, I wouldn't have written it myself because of the tight deadline."

  • Albert

    "Thanks for your cautious eye, attention to detail and overall superb service. Thanks to you, now I am confident that I can submit my term paper on time."

  • Mary

    "Thank you for the GREAT work you have done. Just wanted to tell that I'm very happy with my essay and will get back with more assignments soon."

Ready to tackle your homework?

Place an order