View source for 5g2x


==Structure a of Group II Intron Complexed with its Reverse Transcriptase==
<SX load='5g2x' size='340' side='right' viewer='molstar' caption='[[5g2x]], [[Resolution|resolution]] 3.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5g2x]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Lactococcus_cremoris Lactococcus cremoris] and [https://en.wikipedia.org/wiki/Lactococcus_lactis Lactococcus lactis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5G2X OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5G2X FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.8&#8491;</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=5g2x FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5g2x OCA], [https://pdbe.org/5g2x PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5g2x RCSB], [https://www.ebi.ac.uk/pdbsum/5g2x PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5g2x ProSAT]</span></td></tr>
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== Function ==
[https://www.uniprot.org/uniprot/LTRA_LACLC LTRA_LACLC] Multifunctional protein that promotes group II intron splicing and mobility by acting both on RNA and DNA. It has three activities: reverse transcriptase (RT) for intron duplication, maturase to promote splicing, and DNA endonuclease for site-specific cleavage of recipient alleles. The intron-encoded protein promotes splicing by facilitating the formation of the catalytically active structure of the intron RNA. After splicing, the protein remains bound to the excised intron lariat RNA, forming ribonucleoprotein particles, and cleaving the antisense strand of the recipient DNA in the 3' exon. After DNA cleavage, retrohoming occurs by a target DNA-primed reverse transcription of the intron RNA that had reverse spliced into the sense strand of the recipient DNA. It also contributes to the recognition of the DNA target site and acts as a repressor of its own translation.
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== Publication Abstract from PubMed ==
Bacterial group II introns are large catalytic RNAs related to nuclear spliceosomal introns and eukaryotic retrotransposons. They self-splice, yielding mature RNA, and integrate into DNA as retroelements. A fully active group II intron forms a ribonucleoprotein complex comprising the intron ribozyme and an intron-encoded protein that performs multiple activities including reverse transcription, in which intron RNA is copied into the DNA target. Here we report cryo-EM structures of an endogenously spliced Lactococcus lactis group IIA intron in its ribonucleoprotein complex form at 3.8-A resolution and in its protein-depleted form at 4.5-A resolution, revealing functional coordination of the intron RNA with the protein. Remarkably, the protein structure reveals a close relationship between the reverse transcriptase catalytic domain and telomerase, whereas the active splicing center resembles the spliceosomal Prp8 protein. These extraordinary similarities hint at intricate ancestral relationships and provide new insights into splicing and retromobility.

Structure of a group II intron in complex with its reverse transcriptase.,Qu G, Kaushal PS, Wang J, Shigematsu H, Piazza CL, Agrawal RK, Belfort M, Wang HW Nat Struct Mol Biol. 2016 May 2. doi: 10.1038/nsmb.3220. PMID:27136327<ref>PMID:27136327</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
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[[Category: Lactococcus cremoris]]
[[Category: Lactococcus lactis]]
[[Category: Large Structures]]
[[Category: Agrawal RK]]
[[Category: Belfort M]]
[[Category: Kaushal PS]]
[[Category: Piazza CL]]
[[Category: Qu G]]
[[Category: Shigematsu H]]
[[Category: Wang HW]]
[[Category: Wang J]]