7oif
CspA-27 cotranslational folding intermediate 2
Structural highlights
FunctionRS7_ECOLI One of the primary rRNA binding proteins, it binds directly to 16S rRNA where it nucleates assembly of the head domain of the 30S subunit. Is located at the subunit interface close to the decoding center, where it has been shown to contact mRNA. Has been shown to contact tRNA in both the P and E sites; it probably blocks exit of the E site tRNA.[1] Protein S7 is also a translational repressor protein; it regulates the expression of the str operon members to different degrees by binding to its mRNA.[2] Publication Abstract from PubMedCellular proteins begin to fold as they emerge from the ribosome. The folding landscape of nascent chains is not only shaped by their amino acid sequence but also by the interactions with the ribosome. Here, we combine biophysical methods with cryo-EM structure determination to show that folding of a beta-barrel protein begins with formation of a dynamic alpha-helix inside the ribosome. As the growing peptide reaches the end of the tunnel, the N-terminal part of the nascent chain refolds to a beta-hairpin structure that remains dynamic until its release from the ribosome. Contacts with the ribosome and structure of the peptidyl transferase center depend on nascent chain conformation. These results indicate that proteins may start out as alpha-helices inside the tunnel and switch into their native folds only as they emerge from the ribosome. Moreover, the correlation of nascent chain conformations with reorientation of key residues of the ribosomal peptidyl-transferase center suggest that protein folding could modulate ribosome activity. A switch from alpha-helical to beta-strand conformation during co-translational protein folding.,Agirrezabala X, Samatova E, Macher M, Liutkute M, Maiti M, Gil-Carton D, Novacek J, Valle M, Rodnina MV EMBO J. 2022 Feb 15;41(4):e109175. doi: 10.15252/embj.2021109175. Epub 2022 Jan , 7. PMID:34994471[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
| ||||||||||||||||||||
