4a4i

Crystal structure of the human Lin28b cold shock domain

spinqualitylabelsall models 4a4i, resolution 1.95Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4a4i is a 2 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GOL, SO4 Related: 4a65, 4a76, 4alp Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Disease [LN28B_HUMAN] Neuroblastoma. Function [LN28B_HUMAN] Acts as a suppressor of microRNA (miRNA) biogenesis by specifically binding the precursor let-7 (pre-let-7), a miRNA precursor. Acts by binding pre-let-7 and recruiting ZCCHC11/TUT4 uridylyltransferase, leading to the terminal uridylation of pre-let-7. Uridylated pre-let-7 miRNAs fail to be processed by Dicer and undergo degradation. Specifically recognizes the 5'-GGAG-3' motif in the terminal loop of pre-let-7. Also recognizes and binds non pre-let-7 pre-miRNAs that contain the 5'-GGAG-3' motif in the terminal loop, leading to their terminal uridylation and subsequent degradation. Mediates MYC-mediated let-7 repression. Isoform 1, when overexpressed, stimulates growth of the breast adenocarcinoma cell line MCF-7. Isoform 2 has no effect on cell growth. Publication Abstract from PubMed The RNA-binding protein Lin28 regulates the processing of a developmentally important group of microRNAs, the let-7 family. Lin28 blocks the biogenesis of let-7 in embryonic stem cells and thereby prevents differentiation. It was shown that both RNA-binding domains (RBDs) of this protein, the cold-shock domain (CSD) and the zinc-knuckle domain (ZKD) are indispensable for pri- or pre-let-7 binding and blocking its maturation. Here, we systematically examined the nucleic acid-binding preferences of the Lin28 RBDs and determined the crystal structure of the Lin28 CSD in the absence and presence of nucleic acids. Both RNA-binding domains bind to single-stranded nucleic acids with the ZKD mediating specific binding to a conserved GGAG motif and the CSD showing only limited sequence specificity. However, only the isolated Lin28 CSD, but not the ZKD, can bind with a reasonable affinity to pre-let-7 and thus is able to remodel the terminal loop of pre-let-7 including the Dicer cleavage site. Further mutagenesis studies reveal that the Lin28 CSD induces a conformational change in the terminal loop of pre-let-7 and thereby facilitates a subsequent specific binding of the Lin28 ZKD to the conserved GGAG motif. The Lin28 cold-shock domain remodels pre-let-7 microRNA.,Mayr F, Schutz A, Doge N, Heinemann U Nucleic Acids Res. 2012 May 8. PMID:22570413 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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