This is only 1 of the ficolins introduced by my sensei in the class. L-Ficolin exist in human alongside with H-ficolin and M-ficolin. I didn't want to explain much of these ficolins in human since I'm not involved directly in the study (my labmates is doing research on human ficolins). From the table you can see there are 2 types of ficolins in mouse, which is Ficolin-A & Ficolin-B. What I'm doing currently is the study on Ficolin-A that exist in mouse. Ficolin-A activates the complement system, therefore I focused on the study to Ficolin-A. Currently what my sensei and I is aiming is to prove the ability of Ficolin-A to activates the complement system. This post is only the inroductory part, so I will explain the complement system further in my later post.
I purposely downloaded this picture from PDB and attach it here for our review. It's from the entry 2J61(L-ficolin complexed to n-acetylglucosamine (formE C) in PDB. Well, it's only the L-Ficolin backbone structure so you won't find GlcNAc molecule there. Ficolin consist of 4 domains and this is the fibrinogen domain at the non-reducing terminal residue of the molecule. Besides this part, ficolin has cysteine-rich region on the reducing terminal, collagen-like domain in the middle and short neck-like segment where the collagen-like domain is attached to the fibrinogen domain. In the first picture, you can see the tetramer form of ficolin. 1 ficolin subunit will strangled with another 2 subunit, makes them a 3 subunit that will form a tetramer. As my sensei told, the tetramer will have a good 'avinity', compared to every subunit that have a low affinity toward binding to the glycans.
PDB is a very useful database where you can find a lot of biological molecule structures for your understanding in there. It has 78,000 molecule structures, always updated. How they determine the structure, is by using X-ray diffraction method. Therefore you can find a wide range of resolutions used to examine the structure, where the best resolution suggested is below 3.00 A. Sadly they don't have the Ficolin-A structure determined yet. Well, there is another way to develop A-Ficolin molecule structure, by using Discovey Studio, where I planned to utilise when I have the free time. The software is way too much expensive for a student like me and only 10 PC's in my university installed with that. I really hope someone who have the software can share it with me, hehe.
I will write more on A-Ficolin function, until next time...
