Protein Phosphatase 2C

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Contents 1 This page is under construction 2 ABA-regulated PP2C structures 3 References 4 See Also

This page is under construction

Five plant protein phosphatase 2Cs are essential components of the core ABA Signaling Pathway - ABI1, ABI2, HAB1, HAB2, and PP2CA/AHG3^[1][2][3]of clade A of the plant protein phosphatase 2C family

Left panel - ABI1 3ujk	Middle panel- HAB1 bound to PYL2.ABA 3ujl	Right panel - HAB1 (gold), with Mg2+ and SO42- in complex with SnRK2.6 (blue) 3ujg
spinqualitylabelsall models 3kdh - apo-Pyl2 Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image 3kdh scenes	spinqualitylabelsall models 3ujl - PYR2-HAB1 Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image 3ujl scenes Complex between PYL2 (blue) with bound ABA (CPK spheres)and HAB1 (gold), a protein phosphatase 2C. Magnesium ions in the active site of HAB1 are shown as green spheres. Gate residue proline 92 (blue ball and stick) interacts with typtophan 290 (gold ball and stick and residues in a hydrophobic loop (dark gold ball and stick) of HAB1. The gate also interacts with residues surrounding the phosphatase's active site, which is marked by magnesium ions (small green spheres).	spinqualitylabelsall models 3ujg - SnRK2.6-HAB1 Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image 3ujg scenes The two enzymes are bound via interface their active sites. The phosphatase inactivates the kinase by dephosphorylating the kinase activation loop and by sterically blocking the kinase active site. The complex was constructed as a fusion protein with a 6His-tag at the N-terminus of SnRK2.6 (residues 11–362) fused to HAB1(172–511) via a GSGSAGSAAGS linker. Mutations of D296A and E297A in SnRK2.6 were introduced at the crystal packing interface to reduce surface entropy. The activation loop (blue trace) of SnRK2.6 is inserted into the catalytic site (marked by the magnesium ions) of the phosphatase. The phosphorylatable residue of the activation loop S175 (CPK ball and stick) is positioned near the magnesium ions. W385 of the phosphatase (brown ball and stick) in turn protrudes into the kinase's active site, where it interacts with residues R139 and Glu144 (CPK ball and stick) of the catalytic loop (orchid trace) and I183 of the activation loop. SnRK2.6 is shown in blue cartoon, and HAB1 in gold spacefill. The ABA box sequence is not resolved, but it would extend from the C-terminal end of the SNRK2 box helix (cyan helix). It is proposed that the ABA box sequence, which is highly acidic, binds to a patch of basic residues (blue) on the surface of the phosphatase.[4]

ABA-regulated PP2C structures

3jrq, 3kdj, 3nmn – AtPP2C + Pyl1 – Arabidopsis thaliana
3nmt, 3kb3, 3nmv, 3ujl – AtPP2C + Pyl2
4ds8 – AtPP2C + Pyl3 + Mn
3rt0 – AtPP2C (mutant) + Pyl10
3qn1, 3zvu – AtPP2C + Pyr1
3ujg – AtPP2C + SNRK2
3ujk – AtPP2C

References

1. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Ma2009
2. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Park2009
3. ↑ Yoshida T, Nishimura N, Kitahata N, Kuromori T, Ito T, Asami T, Shinozaki K, Hirayama T. ABA-hypersensitive germination3 encodes a protein phosphatase 2C (AtPP2CA) that strongly regulates abscisic acid signaling during germination among Arabidopsis protein phosphatase 2Cs. Plant Physiol. 2006 Jan;140(1):115-26. Epub 2005 Dec 9. PMID:16339800 doi:10.1104/pp.105.070128
4. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Soon2012

See Also

[1] Abscisic Acid in Wikipedia