The paper:
T. Hessa et al., ?Recognition of transmembrane helices by the endoplasmic reticulum translocon,? Nature, 433:377?81, 2005. (Cited in 88 papers)
The finding:
Gunnar von Heijne at Stockholm University and colleagues systematically altered the sequence of a transmembrane helix segment to understand how the translocon protein complex determines the segment?s placement in a lipid membrane. ?We figured out how to speak to the translocon, and we?re learning what its code is for inserting transmembrane proteins,? says co-author Stephen White from the University of California, Irvine.
The surprise:
It was easy to imagine that a peptide?s interaction with the translocon determined a segment?s location, says von Heijne. But this paper provided evidence that the protein?s interactions with the lipid bilayer are directing the translocon.
The follow-up:
Von Heijne has tested several hundred additional polypeptides in various systems, such as Escherichia coli...
| The numbers: | ||
| Free energy range | Peptides | Favored position |
| <0 kcal/mol | Isoleucine-Valine | Hydrocarbon core |
| -0 kcal/mol | Cysteine-Alanine | Interfacial region |
| >0 kcal/mol | Charged and polar residues | Aqueous layer |
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