Code and Equations for Kinetic Model of Psbs-Dependent Nonphotochemical Quenching

Contents

GUI for general use of model

The model has a GUI interface. A manual for using the GUI can be found here: NPQGUIManual. The code for the GUI Manual can be downloaded here: model Code.

There are two versions of the GUI file with different visual formatting: GUIthylakoidSim_OSX.m, formatted for OS X on the Mac, and GUIthylakoidSim_Windows.m, formatted to look good on Windows. Their functionality should be the same. To run the GUI, run one of these two files, which are contained in the zipped code.

This page and all the linked code was generated using the publish command in MATLAB. The M-code can be retrieved from the html pages using the command grabcode.

Reproducing Figures from Manuscript

This site contains the code for the model of rapidly-reversible nonphotochemical quenching described in the manuscript "A Kinetic Mode of PbsS-Dependent Nonphotochemical Quenching" by Julia Zaks, Kapil Amarnath, David Kramer, Krishna Niyogi, and Graham Fleming.

The simulations portions of Figures 4-6 in the paper can be generated using the scripts

makeFigures

makePamFigures

makeStaticFigures

In order to run the scripts, it is necesary to generate the variable samplepam using the script PamSim.

The images in figure 4 are generated with the script makeFigures. The script also loads and displays experimental data, and makes use of the class pamtraceAv and pamtrace1 to organize the data.

Model Differential Equations

The differential equations for each module (F_1-F_8, described in the Supplementary information) are contained in the following functions

Photosystem II|

qE quenching

Plastoquinone Pool

Cytochrome b6f

Photosystem I

Lumen Flux

ATP Synthase

Reduction of Ferredoxin in Stroma

In order to evaluate values such as the pH gradient, chemical potential gradient, and transmembrane electric field, which are quantities that are not differential equations themselves, these functions call

getStaticThylakoidValues

getStaticQuencherValues

Running a Simulation

1. Setting up Input

To run a simulation, it is necessary to specify the intensity of light that is input to the model and and the duration of light. These need to be specificed in the variables LightIntensity and durat. The light intensity sequence for a PAM trace can be set up with setupPAMIntensities.

2. Running model

chloroplastSim takes a series of light intensities and durations, and sequentially calls

runChloroplastSim, which simulates the variables for a single light intensity. The initial conditions for each section are the final values for the previous section. This function calls the differential equation solver (usually ode15s) and evaluates the differential equations for each module by calling them with the function evolveVars

the function chloroplastSim stitches together the simulations from the different light intensities and returns a struct containing the simulated values, the parameters for the simulation, and auxiliary information.

3. Plotting Resuts

plotvar plots an individual variable for which there is an explicit differential equation

plotStaticValues plots an individual variable that is evaluated by the functions getStaticThylakoidValues and getStaticQuencherValues.

plotStaticVals plots several specific variables.

plotallvars plots all the simulated variables.

plotFlux plots the flux of a given variable by plotting the rate of change from all the different modules that affect that variable.

To calculate NPQ-related parameters, the function getChlorophyllkRates calculates the rates of various quenching pathways for chlorophyll.

4. Example functions

PamSim simulates PAM fluorescence experiment. It is used to generate the data in the paper.

sampleSim

testPSII

The sequence of light intensities used to simulate PAM fluorescence measurements are set up in the script initChloroplastSim.

The parameters used for the simulations are contained in the file params.txt, and are loaded into matlab using the script getparamsfromfilename.

Proper Citation

Any published result that uses this code should cite the paper.