3k3k

From Proteopedia

Crystal structure of dimeric abscisic acid (ABA) receptor pyrabactin resistance 1 (PYR1) with ABA-bound closed-lid and ABA-free open-lid subunits

Structural highlights

3k3k is a 2 chain structure with sequence from Arabidopsis thaliana. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 1.7Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

PYR1_ARATH Receptor for abscisic acid (ABA) required for ABA-mediated responses such as stomatal closure and germination inhibition. Inhibits the activity of group-A protein phosphatases type 2C (PP2Cs) when activated by ABA.^[1] ^[2] ^[3]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

The phytohormone abscisic acid (ABA) acts in seed dormancy, plant development, drought tolerance, and adaptive responses to environmental stresses. Structural mechanisms mediating ABA receptor recognition and signaling remain unknown but are essential for understanding and manipulating abiotic stress resistance. Here, we report structures of pyrabactin resistance 1 (PYR1), a prototypical PYR/PYR1-like (PYL)/regulatory component of ABA receptor (RCAR) protein that functions in early ABA signaling. The crystallographic structure reveals an alpha/beta helix-grip fold and homodimeric assembly, verified in vivo by coimmunoprecipitation. ABA binding within a large internal cavity switches structural motifs distinguishing ABA-free "open-lid" from ABA-bound "closed-lid" conformations. Small-angle x-ray scattering suggests that ABA signals by converting PYR1 to a more compact, symmetric closed-lid dimer. Site-directed PYR1 mutants designed to disrupt hormone binding lose ABA-triggered interactions with type 2C protein phosphatase partners in planta.

Structural mechanism of abscisic acid binding and signaling by dimeric PYR1.,Nishimura N, Hitomi K, Arvai AS, Rambo RP, Hitomi C, Cutler SR, Schroeder JI, Getzoff ED Science. 2009 Dec 4;326(5958):1373-9. Epub 2009 Oct 22. PMID:19933100^[4]

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

References

↑ Santiago J, Rodrigues A, Saez A, Rubio S, Antoni R, Dupeux F, Park SY, Marquez JA, Cutler SR, Rodriguez PL. Modulation of drought resistance by the abscisic acid receptor PYL5 through inhibition of clade A PP2Cs. Plant J. 2009 Nov;60(4):575-88. doi: 10.1111/j.1365-313X.2009.03981.x. Epub 2009 , Jul 16. PMID:19624469 doi:10.1111/j.1365-313X.2009.03981.x
↑ Park SY, Fung P, Nishimura N, Jensen DR, Fujii H, Zhao Y, Lumba S, Santiago J, Rodrigues A, Chow TF, Alfred SE, Bonetta D, Finkelstein R, Provart NJ, Desveaux D, Rodriguez PL, McCourt P, Zhu JK, Schroeder JI, Volkman BF, Cutler SR. Abscisic acid inhibits type 2C protein phosphatases via the PYR/PYL family of START proteins. Science. 2009 May 22;324(5930):1068-71. doi: 10.1126/science.1173041. Epub 2009, Apr 30. PMID:19407142 doi:10.1126/science.1173041
↑ Szostkiewicz I, Richter K, Kepka M, Demmel S, Ma Y, Korte A, Assaad FF, Christmann A, Grill E. Closely related receptor complexes differ in their ABA selectivity and sensitivity. Plant J. 2010 Jan;61(1):25-35. doi: 10.1111/j.1365-313X.2009.04025.x. Epub 2009, Sep 21. PMID:19769575 doi:10.1111/j.1365-313X.2009.04025.x
↑ Nishimura N, Hitomi K, Arvai AS, Rambo RP, Hitomi C, Cutler SR, Schroeder JI, Getzoff ED. Structural mechanism of abscisic acid binding and signaling by dimeric PYR1. Science. 2009 Dec 4;326(5958):1373-9. Epub 2009 Oct 22. PMID:19933100