PDBsum entry 3jc2

Transport protein

PDB id: 3jc2

Contents

Protein chains

401 a.a.

62 a.a.

19 a.a.

32 a.a.

PDB id:

3jc2

Name:

Transport protein

Title:

The structure of the mammalian sec61 channel opened by a signal sequence

Structure:

Protein transport protein sec61 subunit alpha isoform 1. Chain: 1. Synonym: sec61 alpha-1. Protein transport protein sec61 subunit gamma. Chain: 2. Prolactin. Chain: w. Engineered: yes. Protein transport protein sec61 subunit beta.

Source:

Canis lupus familiaris. Dog. Organism_taxid: 9615. Other_details: purified from native canine microsomes. Bos taurus. Bovine. Organism_taxid: 9913. Gene: prolactin. Expressed in: oryctolagus cuniculus.

Authors:

R.M.Voorhees,R.S.Hegde

Key ref:

R.M.Voorhees and R.S.Hegde (2016). Structure of the Sec61 channel opened by a signal sequence. Science, 351, 88-91. PubMed id: 26721998 DOI: 10.1126/science.aad4992

Date:

15-Nov-15 Release date: 13-Jan-16

Protein chain

P38377  (S61A1_CANLF) -  Protein transport protein Sec61 subunit alpha isoform 1 from Canis lupus familiaris

Seq: 476 a.a.

Struc: 401 a.a.

Protein chain

P60058  (SC61G_CANLF) -  Protein transport protein Sec61 subunit gamma from Canis lupus familiaris

Seq: 68 a.a.

Struc: 62 a.a.

Protein chain

P01239  (PRL_BOVIN) -  Prolactin from Bos taurus

Seq: 229 a.a.

Struc: 19 a.a.

Protein chain

No UniProt id for this chain

Struc: 32 a.a.

DOI no: 10.1126/science.aad4992

Science 351:88-91 (2016)

PubMed id: 26721998

Structure of the Sec61 channel opened by a signal sequence.

R.M.Voorhees, R.S.Hegde.

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 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.