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-Structure paper
Title | Structure of the Sec61 channel opened by a signal sequence. |
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Journal, issue, pages | Science, Vol. 351, Issue 6268, Page 88-91, Year 2016 |
Publish date | Jan 1, 2016 |
Authors | Rebecca M Voorhees / Ramanujan S Hegde / |
PubMed Abstract | Secreted and integral membrane proteins compose up to one-third of the biological proteome. These proteins contain hydrophobic signals that direct their translocation across or insertion into the ...Secreted and integral membrane proteins compose up to one-third of the biological proteome. These proteins contain hydrophobic signals that direct their translocation across or insertion into the lipid bilayer by the Sec61 protein-conducting channel. The molecular basis of how hydrophobic signals within a nascent polypeptide trigger channel opening is not understood. Here, we used cryo-electron microscopy to determine the structure of an active Sec61 channel that has been opened by a signal sequence. The signal supplants helix 2 of Sec61α, which triggers a rotation that opens the central pore both axially across the membrane and laterally toward the lipid bilayer. Comparisons with structures of Sec61 in other states suggest a pathway for how hydrophobic signals engage the channel to gain access to the lipid bilayer. |
External links | Science / PubMed:26721998 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.6 Å |
Structure data | |
Source |
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Keywords | TRANSPORT PROTEIN / Sec61 / translocation / signal sequence |