4al7

From Proteopedia

(Difference between revisions)

Revision as of 09:26, 6 March 2019

Crystal structure of the Csy4-minimal crRNA complex

Structural highlights

4al7 is a 2 chain structure with sequence from "bacillus_aeruginosus"_(schroeter_1872)_trevisan_1885 "bacillus aeruginosus" (schroeter 1872) trevisan 1885. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Related:	4al5, 4al6
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

[CAS6_PSEAB] CRISPR (clustered regularly interspaced short palindromic repeat) is an adaptive immune system that provides protection against mobile genetic elements (viruses, transposable elements and conjugative plasmids). CRISPR clusters contain sequences complementary to antecedent mobile elements and target invading nucleic acids. CRISPR clusters are transcribed and processed into CRISPR RNA (crRNA). Processes pre-crRNA into individual crRNA units. Absolutely required for crRNA production or stability. Upon expression in E.coli endonucleolytically processes pre-crRNA, although disruption and reconstitution experiments indicate that in situ other genes are also required for processing. Yields 5'-hydroxy and 3'-phosphate groups. The Csy ribonucleoprotein complex binds target ssDNA with high affinity but target dsDNA with much lower affinity.^[1] ^[2] ^[3]

Publication Abstract from PubMed

CRISPR-Cas adaptive immune systems protect prokaryotes against foreign genetic elements. crRNAs derived from CRISPR loci base pair with complementary nucleic acids, leading to their destruction. In Pseudomonas aeruginosa, crRNA biogenesis requires the endoribonuclease Csy4, which binds and cleaves the repetitive sequence of the CRISPR transcript. Biochemical assays and three co-crystal structures of wild-type and mutant Csy4/RNA complexes reveal a substrate positioning and cleavage mechanism in which a histidine deprotonates the ribosyl 2'-hydroxyl pinned in place by a serine, leading to nucleophilic attack on the scissile phosphate. The active site catalytic dyad lacks a general acid to protonate the leaving group and positively charged residues to stabilize the transition state, explaining why the observed catalytic rate constant is approximately 10(4)-fold slower than that of RNase A. We show that this RNA cleavage step is essential for assembly of the Csy protein-crRNA complex that facilitates target recognition. Considering that Csy4 recognizes a single cellular substrate and sequesters the cleavage product, evolutionary pressure has likely selected for substrate specificity and high-affinity crRNA interactions at the expense of rapid cleavage kinetics.

Csy4 relies on an unusual catalytic dyad to position and cleave CRISPR RNA.,Haurwitz RE, Sternberg SH, Doudna JA EMBO J. 2012 Apr 20. doi: 10.1038/emboj.2012.107. PMID:22522703^[4]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Haurwitz RE, Jinek M, Wiedenheft B, Zhou K, Doudna JA. Sequence- and structure-specific RNA processing by a CRISPR endonuclease. Science. 2010 Sep 10;329(5997):1355-8. PMID:20829488 doi:10.1126/science.1192272
↑ Cady KC, O'Toole GA. Non-identity-mediated CRISPR-bacteriophage interaction mediated via the Csy and Cas3 proteins. J Bacteriol. 2011 Jul;193(14):3433-45. doi: 10.1128/JB.01411-10. Epub 2011 Mar, 11. PMID:21398535 doi:http://dx.doi.org/10.1128/JB.01411-10
↑ Haurwitz RE, Sternberg SH, Doudna JA. Csy4 relies on an unusual catalytic dyad to position and cleave CRISPR RNA. EMBO J. 2012 Apr 20. doi: 10.1038/emboj.2012.107. PMID:22522703 doi:10.1038/emboj.2012.107
↑ Haurwitz RE, Sternberg SH, Doudna JA. Csy4 relies on an unusual catalytic dyad to position and cleave CRISPR RNA. EMBO J. 2012 Apr 20. doi: 10.1038/emboj.2012.107. PMID:22522703 doi:10.1038/emboj.2012.107

1 Structural highlights
2 Function
3 Publication Abstract from PubMed
4 See Also
5 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/4al7"

Categories: Doudna, J A | Haurwitz, R E | Sternberg, S H | Crispr | Hydrolase-rna complex

@@ Line 1: / Line 1: @@
 ==Crystal structure of the Csy4-minimal crRNA complex==
-<StructureSection load='4al7' size='340' side='right' caption='[[4al7]], [[Resolution|resolution]] 2.32&Aring;' scene=''>
+<StructureSection load='4al7' size='340' side='right'caption='[[4al7]], [[Resolution|resolution]] 2.32&Aring;' scene=''>
 == Structural highlights ==
 <table><tr><td colspan='2'>[[4al7]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/"bacillus_aeruginosus"_(schroeter_1872)_trevisan_1885 "bacillus aeruginosus" (schroeter 1872) trevisan 1885]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4AL7 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4AL7 FirstGlance]. <br>
@@ Line 20: / Line 20: @@
 ==See Also==
+*[[CRISPR subtype I-F|CRISPR subtype I-F]]
 *[[Endonuclease|Endonuclease]]
 == References ==

4al7

From Proteopedia

Revision as of 09:26, 6 March 2019

Crystal structure of the Csy4-minimal crRNA complex

Structural highlights

Function

Publication Abstract from PubMed

See Also

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

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