SASDCY9: Oxidised chloroplastic calvin cycle protein CP12 from C. reinhardtii

Basic information

• Entry: Database: SASBDB / ID: SASDCY9

Sample

Oxidised chloroplastic calvin cycle protein CP12 from C. reinhardtii

• Calvin cycle protein CP12, chloroplastic (protein), CP12, Chlamydomonas reinhardtii

Function / homology

Function:

negative regulation of reductive pentose-phosphate cycle / supramolecular complex / reductive pentose-phosphate cycle / nickel cation binding / chloroplast / positive regulation of protein-containing complex assembly / molecular adaptor activity / copper ion binding / enzyme binding / protein-containing complex

Domain/homology:

Calvin cycle protein CP12-like / CP12 domain / CP12

Component:

Calvin cycle protein CP12, chloroplastic

• Biological species: Chlamydomonas reinhardtii (plant)
• Citation: Journal: J Mol Biol / Year: 2018; Title: Cryptic Disorder Out of Disorder: Encounter between Conditionally Disordered CP12 and Glyceraldehyde-3-Phosphate Dehydrogenase.; Authors: Hélène Launay / Patrick Barré / Carine Puppo / Yizhi Zhang / Stéphanie Maneville / Brigitte Gontero / Véronique Receveur-Bréchot / ; Abstract: Among intrinsically disordered proteins, conditionally disordered proteins undergo dramatic structural disorder rearrangements upon environmental changes and/or post-translational modifications that directly modulate their function. Quantifying the dynamics of these fluctuating proteins is extremely challenging but paramount to understanding the regulation of their function. The chloroplast protein CP12 is a model of such proteins and acts as a redox switch by formation/disruption of its two disulfide bridges. It regulates the Calvin cycle by forming, in oxidized conditions, a supramolecular complex with glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and then phosphoribulokinase. In this complex, both enzymes are inactive. The highly dynamic nature of CP12 has so far hindered structural characterization explaining its mode of action. Thanks to a synergistic combination of small-angle X-ray scattering, nuclear magnetic resonance and circular dichroism that drove the molecular modeling of structural ensembles, we deciphered the structural behavior of Chlamydomonas reinhardtii oxidized CP12 alone and in the presence of GAPDH. Contrary to sequence-based structural predictions, the N-terminal region is unstable, oscillates at the ms timescale between helical and random conformations, and is connected through a disordered linker to its C-terminus, which forms a stable helical turn. Upon binding to GAPDH, oxidized CP12 undergoes an induced unfolding of its N-terminus. This phenomenon called cryptic disorder contributes to decrease the entropy cost and explains CP12 unusual high affinity for its partners.

Contact author

• Veronique Receveur-Brechot (Aix Marseille Univ, CNRS, BIP UMR7281, Marseille, France)

Models

• Model #1697: ; Type: dummy / Radius of dummy atoms: 1.90 A / Chi-square value: 2.84 / P-value: 0.000022; Search similar-shape structures of this assembly by Omokage search (details)
• Model #1698: ; Type: dummy / Radius of dummy atoms: 2.00 A / Symmetry: P1 / Chi-square value: 2.367 / P-value: 0.793560; Search similar-shape structures of this assembly by Omokage search (details)

Sample

• Sample: Name: Oxidised chloroplastic calvin cycle protein CP12 from C. reinhardtii; Specimen concentration: 0.54 mg/ml
• Buffer: Name: 50 mM phosphate buffer, 50 mM NaCl, 20 mM oxidized DTT; pH: 6.5

Entity #907

Name: CP12 / Type: protein / Description: Calvin cycle protein CP12, chloroplastic / Formula weight: 10.934 / Num. of mol.: 1 / Source: Chlamydomonas reinhardtii / References: UniProt: A6Q0K5
Sequence:

HHHHHHHHHH SSGHIEGRHM SGQPAVDLNK KVQDAVKEAE DACAKGTSAD CAVAWDTVEE LSAAVSHKKD AVKADVTLTD PLEAFCKDAP DADECRVYED

Experimental information

• Beam: Instrument name: SOLEIL SWING / City: Saint-Aubin / 国: France / Type of source: X-ray synchrotronSynchrotron / Wavelength: 0.1033 Å / Dist. spec. to detc.: 1.79 mm
• Detector: Name: AVIEX PCCD170170 / Type: CCD

Scan

Title: Oxidised chloroplastic calvin cycle protein CP12 from C. reinhardtii
Measurement date: Nov 3, 2015 / Storage temperature: 15 °C / Cell temperature: 20 °C / Exposure time: 1.5 sec. / Number of frames: 250 / Unit: 1/A /

	Min	Max
Q	0.0181	0.467

Distance distribution function P(R)

Sofotware P(R): GNOM 4.6 / Number of points: 398 /

	Min	Max
Q	0.01842	0.467
P(R) point	1	398
R	0	100

Result

Type of curve: sec

	Experimental	Standard	Porod
MW	12.65 kDa	12.65 kDa	-
Volume	-	-	22.48 nm3

	P(R)	P(R) error	Guinier	Guinier error
Forward scattering, I0	0.003974	1.081E-5	0.0039	5.0E-5
Radius of gyration, Rg	2.46 nm	0.01	2.3 nm	0.01

	Min	Max	Error
D	-	10	0.2
Guinier point	6	43	-