Part:BBa_K2117003

Human proinsulin codon-optimised for Y. lipolytica

This part encodes the human proinsulin peptide. The gene has been codon-optimized for the yeast Yarrowia lipolytica using a DTU-Denmark iGEM 2016 team designed codon-optimization tool that also considers illegal restriction sites.

Usage and Biology

Insulin is a peptrode hormone synthesised in the pacreas, and plays a crucial role in glucose homeostasis and prevents harmful levels of sugar in the blood. Beta-cells in the islets of the pancreas release insulin to the blood stream, which stimulates muscle fat and liver cells to absorb and store glucose from the bloodstream by interacting with insulin-specific receptors¹.

At the first stage insulin is synthesized as a chain of 101 amino acids, called preproinsulin with a molecular weight of 12 Kilo daltons (kDa), which comprises of signal peptide (pre-peptide) and three short chains: A, B and C. The pre-peptide, responsible for directing a nascent polypeptide, is removed from preproinsulin giving the proinsulin consisting of 86 amino acids with a molecular weight of 9.4kDa. Subsequently, the proinsulin is folded and two disulphide bonds are created between chain A and B and one links chain A. In the last step, the C chain is digested from the proinsulin by an exoprotease - carboxypeptidase E. The mature insulin contains chains A and B linked by 3 disulphide bonds and in total comprises of 51 amino acids with a molecular weight of 5.8kDa². The maturation of preproinsulin into proinsulin and finally mature insulin is shown in Figure 1.

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Figure 1: Schematic representation of the maturation of preproinsulin into proinsulin and finally mature insulin. The colors represents the following: Pink: Signal peptide, yellow: B chain, green: C chain, Blue: A chain, red: Disulphide bonds. The proteolytic events is carried out by the carboxypeptidase E. Figure from http://watcut.uwaterloo.ca/webnotes/Metabolism/Hormones.html#hormonesInsulinwatcut.com".

References: * 1. https://www.niddk.nih.gov/health-information/diabetes/types/prediabetes-insulin-resistance * 2. Baeshen, N. A., Baeshen, M. N., Sheikh, A., Bora, R. S., Ahmed, M. M. M., Ramadan, H. A. I., … Redwan, E. M. (2014). Cell factories for insulin production. Microbial Cell Factories, 13(1), 141. doi:10.1186/s12934-014-0141-0

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]