Anti-Life: Can we make live with reverse handedness

[Mr Skeptic]

So life is made from chemicals with specific handedness. But as far as I know, it should in theory work just as well with all the handedness reversed. I'm not sure if we could actually make one though, due to technological difficulties. If we could make life with the opposite handedness, how would you go about making it?

 

And a related question, could we eat the result?

[ydoaPs]

Pray to a left-handed god.

[insane_alien]

we could eat the result fine. although it may not have the same nutritional benefit. such as with glucose.

 

there are two forms of glucose, L-glucose and the common D-Glucose(reffered to as dextrose in food and pharma) dextrose will taste sweet and can be metabolised while L-glucose tastes slightly less sweet and cannot be metabolised(makes a good sweetner)

[mississippichem]

We could synthesize bio-molecules of the opposite chirality [i.e. D versus L amino acids], but it is expensive and cumbersome as we can't use natural products as a major feedstock in many cases. Stereo-isomerization of amino-acids is not fun; multi-step process, requires strict control of conditions to avoid side reactions.

I think our best bet would be to genetically engineer a micro organism to do the chemical dirty work for us by consuming achiral nutrients and producing "unnaturally chiral" biochemicals

[mooeypoo]

So life is made from chemicals with specific handedness. But as far as I know, it should in theory work just as well with all the handedness reversed. I'm not sure if we could actually make one though, due to technological difficulties. If we could make life with the opposite handedness, how would you go about making it?

 

And a related question, could we eat the result?

 

STUPIDEST QUESTION EVER (go easy on me, I'm a physicist, not a biologist): What do you mean 'specific handedness'? I assume you don't mean 'right handed' people or (like me!) the brilliant left-handed people.

 

What's "Handedness" in this context?

[ydoaPs]

STUPIDEST QUESTION EVER (go easy on me, I'm a physicist, not a biologist): What do you mean 'specific handedness'? I assume you don't mean 'right handed' people or (like me!) the brilliant left-handed people.

 

What's "Handedness" in this context?

http://en.wikipedia.org/wiki/Chirality_(chemistry)

 

Wikipedia is your friend

[Mr Skeptic]

It's more properly known as "chirality", but it is the equivalent of your right and left hands at the molecular level. Basically, they are mirror images such that the mirror images are different.

[mississippichem]

STUPIDEST QUESTION EVER (go easy on me, I'm a physicist, not a biologist): What do you mean 'specific handedness'? I assume you don't mean 'right handed' people or (like me!) the brilliant left-handed people.

 

What's "Handedness" in this context?

 

I'll save you some time. Chirality is the chemical term for "handedness". This is a measure of the ability of a non-centrosymmetric molecule to rotate a plane of polarized light. In organic chermistry we use the formalisms R and S to say right and left handed respectivley. Biochemistry uses D and L, Inorganic chemistry uses [math]\Delta[/math] and [math]\Lambda[/math].

Edited August 15, 2010 by mississippichem

[TheTheoretician]

This is not theoretically possible without inverting all the chiralities of physical particles and amino acids and sugars and nucleotides all the way from the Origin of the Universe to the emergence of the first cell.

 

Peace,

 

Ik

[PhDwannabe]

This is not theoretically possible without inverting all the chiralities of physical particles and amino acids and sugars and nucleotides all the way from the Origin of the Universe to the emergence of the first cell.

 

Peace,

 

Ik

 

 

Shouldn't there also be something in here about a gyre? I feel like there's a gyre missing.

[TheTheoretician]

Good one, PhDwannabe, yes, gyres are levoral and dextral, accounting for the two hands that I use on this keyboard and the chiralities that exist throughout the cosmological, physical, chemical, and biological realms.

 

Here's how the model puts Pasteur's ghost to rest.

Peace,

 

Ik

[PhDwannabe]

Good one, PhDwannabe, yes, gyres are levoral and dextral, accounting for the two hands that I use on this keyboard and the chiralities that exist throughout the cosmological, physical, chemical, and biological realms.

 

 

<whispering to self> ...dextral, yes... Yes, that clears things up significantly.

[TheTheoretician]

Yes, dextral (right-handed chirality, gyrates counter-clockwise when viewed en face - bottom of image) and levoral (left-handed chirality, gyrates clockwise when viewed en face - top of image). Here's a heuristic (hopefully it works, first time uploading image):

 

Peace,

 

Ik

 

Edit: Good, the image appears. Knowing that will be helpful in terms of facilitating discussion and explaining how I exist and work in the Universe.

Edited August 17, 2010 by TheTheoretician

[BurningKrome]

My understanding is the majority of organic molecules found in life on earth are L- (left handed). There is no functional reason that life could not have evolved (here or elsewhere) using predominantly D- (right handed) molecules...however, we cannot substitute D- for L- in our biological needs.*

 

For example, Motrin is a chiral molecule. Because of the difficulty in separating D- from L-, Motrin tablets contain an equal dispersion (racemic) mix of L- and D-...however only the L- enantiomer is functional. The D- enantiomer is simply disposed of by the liver.

 

Thus, theoretically, when Captain Kirk (or Stargate Universe if I want to update) travel around foreign planets to find food, there is at least a 50/50 odds that the food they found would be incompatible with our biology. I don't know under what circumstances this incompatibility would be toxic...but the aforementioned Motrin example infers it would just be a waste of food.

 

Perhaps the real purpose in engineering D- enantiomer foodstuffs would be to create the next big diet craze?

 

Interesting link...

 

http://en.wikipedia....popular_fiction

 

* From the MIT lecture series "MIT OCW: 7.012: Introduction to Biology" available from iTunes"

Edited September 29, 2010 by BurningKrome

[ydoaPs]

Thus, theoretically, when Captain Kirk (or Stargate Universe if I want to update) travel around foreign planets to find food, there is at least a 50/50 odds that the food they found would be incompatible with our biology. I don't know under what circumstances this incompatibility would be toxic...but the aforementioned Motrin example infers it would just be a waste of food.

In both Star Trek and Stargate, life throughout the galaxy was seeded from life evolved on Earth.

[BurningKrome]

In both Star Trek and Stargate, life throughout the galaxy was seeded from life evolved on Earth.

Sorry. That is true. I forgot to check the footnotes ;-D