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How does the presence/absence of Sec63 affect the Sec61α conformations in yeast?

Publication Type : Journal Article

Source : PLoS computational biology

Url :,substrates%20nearby%20the%20lateral%20gate.

Campus : Coimbatore

School : Computational Engineering and Networking

Center : Center for Computational Engineering and Networking

Year : 2021

Abstract : The Sec complex catalyzes the translocation of proteins of the secretory pathway into the endoplasmic reticulum and the integration of membrane proteins into the endoplasmic reticulum membrane. Some substrate peptides require the presence and involvement of accessory proteins such as Sec63. Recently, a structure of the Sec complex from Saccharomyces cerevisiae, consisting of the Sec61 channel and the Sec62, Sec63, Sec71 and Sec72 proteins was determined by cryo-electron microscopy (cryo-EM). Here, we show by co-precipitation that the Sec61 channel subunit Sbh1 is not required for formation of stable Sec63-Sec61 contacts. Molecular dynamics simulations started from the cryo-EM conformation of Sec61 bound to Sec63 and of unbound Sec61 revealed how Sec63 affects the conformation of Sec61 lateral gate, plug, pore region and pore ring diameter via three intermolecular contact regions. Molecular docking of SRP-dependent vs. SRP-independent signal peptide chains into the Sec61 channel showed that the pore regions affected by presence/absence of Sec63 play a crucial role in positioning the signal anchors of SRP-dependent substrates nearby the lateral gate.

Cite this Research Publication : Pratiti Bhadra; Lalitha Yadhanapudi; Karin R¨omisch; Volkhard Helms “How does the presence/absence of Sec63 affect the Sec61α conformations in yeast?” . PLoS computational biology 17.3 (2021): e1008855.

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