New & Noteworthy
May 11, 2012
Imagine scouring the beaches of the world for balls of whale vomit. People are willing to do this because finding one is like finding a huge gold nugget. Perfume companies will pay around $10,000 per pound for this ambergris (which is the more scientific name for the stuff).
Of course perfume companies would rather have a more reliable and less expensive source for their ambergris. And it wouldn’t hurt to find one that was a little less ethically troubling than using products from an endangered animal.
Until recently their best bet was a chemical called cis-abienol from balsam firs. While less murky ethically, this chemical is tricky to harvest and even trickier to synthesize in the lab. The perfume industry could definitely use an alternative. And researchers in the Bohlmann lab may be on their way to finding it.
In a recent study from this lab, Zerbe and coworkers used “…metabolite profiling, tissue-specific deep transcriptome sequencing and functional (i.e. biochemical) genomics…” to identify the key enzyme for making cis-abienol in balsam firs. They next plan to put the gene into yeast and have the yeast crank out this chemical.
Finding the gene was not trivial. The first thing they did was to identify that most of the cis-abienol was made in the bark and phloem of the balsam fir. They then sequenced the transcriptome from these sources and looked for likely candidate genes. For this last step, they used a curated library of 146 known terpene synthases.
They found 4 candidate genes (AbdiTPS1-4) and successfully cloned three of them. They then went on to express these proteins in E. coli, purify them, and found that AbdiTPS4 catalyzed the synthesis of cis-abienol in vitro. They renamed the gene AbCAS at that point.
According to Dr. Bohlmann, the lab is now testing conditions for getting the enzyme to work in yeast. If they can pull it off, the perfume industry will finally get a cheap and easy alternative to whale vomit. Let’s see if they pass any savings down to the consumer…
by D. Barry Starr, Ph.D., Director of Outreach Activities, Stanford Genetics