TLR 3
From Biocrawler, the free encyclopedia.
TLR 3 is one of 11 Toll-like receptors part of the innate immune system. The protein is described as a large horseshoe-shaped coil composed of 23 leucine-rich repeats (LRRs). TLR3 recognizes double-stranded RNA which is the form of genetic information carried by many viruses. In june 2005 the Scripps Research Institute reported that the structure for this protein was solved.
TLR3 has many repeating leucine-rich repeat units on the outside of the cell membrane and reveals the potential binding site for its ligand, double-stranded RNA.
TLR3 forms a large horseshoe shape that contacts with a neighboring horseshoe, forming a “dimer” of two horseshoes. Much of the TLR3 protein surface is covered with sugar molecules making it a glycoprotein, but on one face that includes the interface between these two horseshoes, there is a large surface that is sugar-free, suggesting that this is where the TLR3 might bind to its target molecule. This surface also contains two distinct patches that are rich in positively-charged residues, suggesting it as a possible binding site for negatively-charged double-stranded RNA.
Despite being a glycoprotein TLR3 crystallises readily which is a prerequisite for structure elucidation by x-ray crystallography.
References
- Scripps Research Institute press release June 21 2005
