Source 1primary paper2015PLoS ONE
Toolkit/Jα-helix of LOV2
Jα-helix of LOV2
Also known as: Jα-helix
Taxonomy: Mechanism Branch / Component. Workflows sit above the mechanism and technique branches rather than replacing them.
Summary
The Jα-helix of LOV2 is a C-terminal helix located downstream of the LOV2 domain in Arabidopsis phototropin1. Evidence from blue-light-dependent trypsin digestion indicates that this helix undergoes a light-responsive structural change and participates in intramolecular signal transmission toward the kinase region.
Usefulness & Problems
Why this is useful
This element is useful as a defined structural output region of the LOV2 photosensory module for studying how blue-light perception is converted into downstream conformational signaling. The available evidence specifically supports its use as a readout of light-induced structural propagation within phototropin1.
Problem solved
The Jα-helix helps localize where blue-light-triggered conformational signaling reaches within the LOV2-kinase region of Arabidopsis phototropin1. It addresses the mechanistic problem of identifying structural intermediates in signal transfer from the LOV2 photosensor to kinase activation.
Taxonomy & Function
Primary hierarchy
Mechanism Branch
Component: A low-level protein part used inside a larger architecture that realizes a mechanism.
Techniques
Structural CharacterizationTarget processes
signalingInput: Light
Implementation Constraints
The supplied evidence places the Jα-helix downstream of the LOV2 C-terminus and assesses its behavior by light-dependent trypsin digestion, including cleavage at Lys603. Mutational context involving Glu474Ala and Lys475Ala in the A'α/Aβ gap was used to probe whether signal propagation to the Jα-helix is preserved despite loss of kinase activation.
The evidence is limited to structural and protease-sensitivity observations in Arabidopsis phototropin1 and does not establish the Jα-helix as a standalone engineered actuator. Quantitative performance parameters, transferability to other systems, and independent validation are not provided in the supplied evidence.
Validation
Cell-freeBacteriaMammalianMouseHumanTherapeuticIndep. Replication
Supporting Sources
Ranked Claims
Light-dependent trypsin digestion at Lys603 and Lys475 indicates blue-light-induced structural changes in both the Jα-helix and the A'α/Aβ gap.
Trypsin digested the LOV2-STK at Lys603 and Lys475 in a light-dependent manner indicating BL-induced structural changes in both the Jα-helix and the gap. The digestion at Lys603 is faster than at Lys475.
Section: abstract
relative digestion rate Lys603 faster than Lys475
In Glu474Ala and Lys475Ala substitutes, the blue-light signal reaches the Jα-helix and the A'α/Aβ gap but does not activate the kinase.
These BL-induced structural changes were observed with the Glu474Ala and the Lys475Ala substitutes, indicating that the BL signal reached the Jα-helix as well as the A'α/Aβ gap but could not activate STK.
Section: abstract
Approval Evidence
1 source2 linked approval claimsfirst-pass slug j-helix-of-lov2
a Jα-helix residing downstream of the LOV2 C-terminus
Source:
light dependent structural changesupports
Light-dependent trypsin digestion at Lys603 and Lys475 indicates blue-light-induced structural changes in both the Jα-helix and the A'α/Aβ gap.
Trypsin digested the LOV2-STK at Lys603 and Lys475 in a light-dependent manner indicating BL-induced structural changes in both the Jα-helix and the gap. The digestion at Lys603 is faster than at Lys475.
Source:
signal propagation failure pointsupports
In Glu474Ala and Lys475Ala substitutes, the blue-light signal reaches the Jα-helix and the A'α/Aβ gap but does not activate the kinase.
These BL-induced structural changes were observed with the Glu474Ala and the Lys475Ala substitutes, indicating that the BL signal reached the Jα-helix as well as the A'α/Aβ gap but could not activate STK.
Source:
Comparisons
Source-backed strengths
Blue-light-dependent protease sensitivity at Lys603 provides direct evidence that the Jα-helix changes structure upon illumination. Mutational analysis in Glu474Ala and Lys475Ala backgrounds further indicates that the light signal can reach the Jα-helix even when kinase activation fails, separating signal propagation from catalytic output.
Ranked Citations
- 1.