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#nascent proteins

2 public questions tagged with this topic.

Protein Sorting and Trafficking

The function of the SRP (Signal Recognition Particle) is to:

Signal recognition particle integrates targeting and translation control to ensure secretory proteins avoid premature cytosolic folding and aggregation. Particle consists of 7SL RNA scaffold folding into Alu and S domains and six proteins. Most critical subunit SRP54 contains N domain four-helix bundle, central GTPase domain and C-terminal M domain rich in methionines that forms deep groove accommodating diverse hydrophobic signal sequences through flexible sulfur-containing side chains providing plastic hydrophobic surface adaptable to many sequences. Binding occurs when signal emerges from r

Ref: Egea et al., Curr Opin Struct Biol 15: 2005, SRP Function in Signal Recognition and Pause.

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Protein Sorting and Trafficking

Which of the following recognizes the signal sequence of nascent proteins targeting the ER?

Early sorting of nascent secretory and membrane proteins is performed by signal recognition particle, conserved ribonucleoprotein containing 7SL RNA scaffold and six protein subunits. When hydrophobic signal sequence of about eight to twelve non-polar residues emerges from ribosomal exit tunnel, methionine-rich M domain of SRP54 forms flexible hydrophobic groove whose abundance of sulfur-containing methionine side chains allows plastic accommodation of diverse signal sequences via induced fit. Binding is communicated through 7SL RNA to Alu domain comprised of SRP9 and SRP14 heterodimer that do

Ref: Lodish et al., Molecular Cell Biology, 9th ed., Chapter 13: SRP Recognizes Signal Sequences.

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