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Structure of a prehandover mammalian ribosomal SRP and SRP receptor targeting complexStructure of a prehandover mammalian ribosomal SRP and SRP receptor targeting complex
Structural highlights
Function[SRP14_CANLF] Signal-recognition-particle assembly has a crucial role in targeting secretory proteins to the rough endoplasmic reticulum membrane. SRP9 together with SRP14 and the Alu portion of the SRP RNA, constitutes the elongation arrest domain of SRP. The complex of SRP9 and SRP14 is required for SRP RNA binding. [SRP54_CANLF] Binds to the signal sequence of presecretory protein when they emerge from the ribosomes and transfers them to TRAM (translocating chain-associating membrane protein). Publication Abstract from PubMedSignal recognition particle (SRP) targets proteins to the endoplasmic reticulum (ER). SRP recognizes the ribosome synthesizing a signal sequence and delivers it to the SRP receptor (SR) on the ER membrane followed by the transfer of the signal sequence to the translocon. Here, we present the cryo-EM structure of the mammalian translating ribosome in complex with SRP and SR in a conformation preceding signal sequence handover. The structure visualizes all eukaryotic-specific SRP and SR proteins and reveals their roles in stabilizing this conformation by forming a large protein assembly at the distal site of SRP RNA. We provide biochemical evidence that the GTP hydrolysis of SRP*SR is delayed at this stage, possibly to provide a time window for signal sequence handover to the translocon. Structure of a prehandover mammalian ribosomal SRP*SRP receptor targeting complex.,Kobayashi K, Jomaa A, Lee JH, Chandrasekar S, Boehringer D, Shan SO, Ban N Science. 2018 Mar 22. pii: science.aar7924. doi: 10.1126/science.aar7924. PMID:29567807[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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