The tag is a particular sequence of the amino-acid units of which all proteins are composed.
The shape that the amino-acid chain wraps itself up into is critical to its function.
Both rely on having a protein's amino-acid sequence in the bag, and both have strengths and weaknesses.
To corroborate the result he also tried p-benzoylphenylalanine, a second large and unnatural addition to the amino-acid dictionary.
In doing that calculation, it helps a lot if you know what the atoms in question are in other words, the amino-acid sequence.
Dr Hahn has, however, found nine places along the amino-acid chain of killifish AHR where the link in the chain varies between individuals.
Chelation, from the Greek for "claw, " employs amino-acid-based chemicals that latch onto lead, mercury and other metals, allowing the body to more easily excrete them.
Judging from the winners' models, reliable extrapolations could be made from one protein to another so long as the two shared at least 30% of their amino-acid sequences.
The molecules of this protein are more or less globular, and are held in that shape by internal cross-links between different parts of the amino-acid chain of which the protein is composed.
They looked at the Pfam database, a repository of the amino-acid sequences of 260, 000 protein domains, to find out how easily, using the 30% figure as a guide, these could be clustered into groups that were single units from an analytical standpoint.
It seems to stimulate overeating by speeding up production of a chemical messenger in the brain called GABA, or gamma-amino butyric acid.
But future research is also likely to focus on the 70-plus amino acid changes that distinguish modern humans from Neanderthals.
However, exercise had a much greater effect on animals that were also given the supplement amino acid L-argenine, and antioxidant vitamins C and E.
But, in older animals - and, it is believed, humans - the amino acid stimulus prompting synthesis is less effective, and the process slows down.
They did, though, give a warm response to N-acetyl-cysteine - an amino acid supplement sold in health food stores, thought to work by increasing the body's ability to mop up destructive chemicals which build up in the liver as enzymes break down ethanol.
If the difference in weight matches one particular amino acid, gene-sequencing can be bypassed altogether.
Five years ago Pioneer Hi-Bred International (a subsidiary of DuPont) figured out how to slide a critical gene from corn into sorghum to make a variant with more lysine--an essential amino acid.
Niteworks is made from L-arginine, an amino acid that helps produce nitric oxide.
L-Tyrosine: L-Tyrosine is an amino acid found in high protein foods.
L-Phenylalanine: L-Phenylalanine is an amino acid found in milk.
Each of these could be linked to a new, unnatural amino acid, which could then be slipped into living cells and incorporated into never-before-seen proteins.
ECONOMIST: Chemists are trying to synthesise new varieties of life
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