Spinach Major Light-Harvesting Complex

This molecule is Light Harvesting Complex-II (LHC-II), which as its name implies, is a major light-harvesting complex of photosynthesis II.  In green plants this is the major solar energy collector, and is the most prevalent and essential membrane protein in chloroplasts.  It is located in the thylakoid membrane and binds half of the thylakoid chlorophyll molecules.  Each monomer of this trimer is made up of 232 amino acids, 13-15 chla and chlb molecules, 3-4 caretonoids, and 1 bound phospholipid.1

Original Setting

Stop Spin

Space-fill

Flipping to 90 degrees to show the top down model, of the three monomers, and you can also flip it back to view the side membrane view of the molecule

Cartoon Structure and Space-fill rotate it around to see the monomers in the top-down view and the side membrane view

Cartoon Structure notice the alpha helices are located in the middle of the molecule (rotate to 90 degrees to notice this)

Electrostatic Surface Potential (Red indicates negative potential, blue indicates positive potential, some load time)  notice the white, non-polar center, which indicates the molecule's orientation in the membrane

Flipping the Electrostatic Surface Potential 90 degrees shows how the molecule is lined up in the membrane (the white, non-polar interior)

Structure of Protein

Original Setting

Stop Spin

Subunit 1 these show the amino acids and the chlorophyll in each monomer

Subunit 2

Subunit 3

All hetero atoms these atoms are located around the alpha helices of each subunit

Chlorophylls on one of the subunits WOW! This shows both chlorophyll a and chlorophyll b, as well as the carotenoids.  Notice that the molecule is largely made up of chlorophyll and caretonoids, and the protein just seems to be there to support them.

 

Created by: Alison Stortz and Kara VonderHaar

1.  Zhenfeng Liu, Hanchi Yan, Kebin Wang, Tingyun Kuang, Jiping Zhang, Lulu Gui, Xiaomin An & Wenrui Chang, Crystal structure of spinach major lightharvesting complex at 2.72A° resolution, Nature Vol 428, 18 March 2004.