Part:BBa_K1403002
Paris Bettencourt 2014 Odor Palette
Our odor palette is composed of BioBricks containing codon-optimized sequences of enzymes known to catalyze reactions that yield volatile compounds with distinctive smells.
We included odors with different tonalities in order to explore the aromas resulting from combinations of smelly units in E. coli. The tonality of each smell is categorized as butter, balminess, citrus, non-citrus fruit and herbal. These cover half of the main odor categories perceivable to human beings.
Each part has a standardized architecture consisting on a constitutive promoter and a functional RBS. The palette could be used as an educational tool to introduce synthetic biology concepts to the general public.
| System | Enzyme | Substrate | Concentration | Product |
|---|---|---|---|---|
| Jasmine BBa_K1403006 | JMT | Jasmonic acid | 1 mM | Methyl jasmonate |
| Mint BBa_K1403009 | BMST1 | Salicylic acid | 2 mM | Methyl salicylate |
| Banana BBa_K1403012 | ATF1 | Isoamyl alcohol | 5 mM | Isoamyl acetate |
| Limonene BBa_K1403003 | LIMS1 | Farnesyl diphosphate | Natural | (+)-Limonene |
| Rain BBa_K1403013 | GDS | Farnesyl diphosphate | Natural | Geosmin |
| Flowers BBa_K1403009 | BMST1 | Benzoic acid | 5 mM | Methyl benzoate |
| Butter BBa_K1403017 & BBa_K1403019 | AldB ilvB/N | Acetolactic acid Pyruvate | Natural | Acetoin |
| Sweat BBa_K1403002 | agaA | 3-M-2-hexenoic acid | - | 3-HO-3-Methylhexanoic acid |
AgaA expression (3M2H-> 3H3MH)
AgaA is an enzyme present in Corynebacterium striatum that is the main responsible for body odor. It is an aminocylase that hydrolyzes 3-methyl-2-hexenoyl-glutamine (3M2H-gln) into 3-methyl-2-hexenoic acid (3M2H) and free glutamine. The substrate is secreted in sweat, and the product is a distinctive armpit odor.
Usage and Biology
Body odor is a complex combination of odorants, but the major components come from just a few known enzymes. In the armpit, for example, a major souce of "pungent" or "musky" odors is the enzyme AgaA expressed by Corynebacterium striatum (Kligman et al., 1981).
Characterization
To understand the smell created by AgaA, we cloned the gene into E. coli (BBa_K1403002). A noticeable odor was produced by agaA-expressing E. coli grown in selective LB, described as "beer-like" or "cheese-like". We confirmed this observation with a formal double-blind smell test (Fig. 1). Also, we sequenced-verified the plasmid. Although the native substrate of the enzyme is not present in LB, the enzyme is known to have a low specificity for the acyl group, and to act on a range of glutamine conjugates (Natsch et al., 2003). These observations highlight the remarkable affect of single gene on the odor profile of a bacterial population.
Fig 1: 14 people smelled two tubes of E. coli grown to saturation in LB. One culture carried synthetic agaA and other an empty vector control. 13 people out of 14 rated the E. coli carrying agaA as more smelly (pink) than the control(violet). Experiments were double-blind. Significance was confirmed by Chi square test (p-value = 0.001341).
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Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21INCOMPATIBLE WITH RFC[21]Illegal BamHI site found at 288
Illegal BamHI site found at 519 - 23COMPATIBLE WITH RFC[23]
- 25INCOMPATIBLE WITH RFC[25]Illegal AgeI site found at 181
- 1000COMPATIBLE WITH RFC[1000]
| None |