In addition to the above mentioned references you can also see: Charcot-Leyden crystals (http://www.ncbi.nlm.nih.gov/pubmed/6508005)
and my own ( :) ) figure 1 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1618374/figure/f1/ Cheers, Artem On Fri, Feb 15, 2013 at 11:46 PM, Zhijie Li <zhijie...@utoronto.ca> wrote: > ** > Hi Jacob, > > Interesting topic. > > This reminds me the posters I saw on ACA 2010, on the femto-second > infrared laser based instrument . That instrument utilizes the nonlinear > optical properties of crystals of chiral molecules to detect very small > crystalline materials from amorphous background: the crystals will double > the frequency of the laser, turning the infrared light to visible light. I > cannot recall the exact name of the technology now, unfortunately. > > Your case of observing in vivo GFP crystals is a little special in that > the crystals are fluorescent. I guess if we scan cells over-expressing > proteins with the above mentioned instrument, we might find that many > proteins will do the same in cells. > > Naturally occurring *in vivo *crystals are not very rare. If we do not > restrict the topic to proteins, then it is well known that many viruses > readily crystallize in the host cell's nuclei and the resulting crystals or > crystalline arrays can be observed under EM. And if we do not restrict the > cells to mammalian cells, then there come the famous BT crystals. > > In addition, I just did some internet search and here are some interesting > results: > > 1) Viral protein crystals can form in HEK cells infected by adenovirus ( > http://www.plosone.org/article/info:doi/10.1371/journal.pone.0002894) > 2) Bacterial infection can cause the infected epithelial cells to form > pathological crystal-containing inclusion bodies in the cytosol ( > http://www.ncbi.nlm.nih.gov/pubmed/8940763). > 3) Crystalline inclusion bodies are found in rabbit embryos ( > http://dev.biologists.org/content/44/1/31.full.pdf) and epididymis of the > nine-banded armadillo( > http://www.sciencedirect.com/science/article/pii/S0022532073800073). > Actually if google "crystalline inclusion body", there will be tons of > literatures. > 4) IgG crystallized in the ER when over expressed from a highly optimized > CHO expression system (http://www.jbc.org/content/286/22/19917.abstract). > This is particularly interesting as we know that whole IgGs are not so > prone to crystallize, although the author do state that "Crystallizing > propensity was due to the intrinsic physicochemical properties of the model > IgG". > > > Given the prevalence of *in vivo* crystallization, especially considering > their correlation with inclusion bodies, I think it is reasonable to > suspect that there are some cases that the inclusion bodies formed during > over expression of transgenic proteins in *E. coli* are crystalline. I > expect that we will be enlightened on this issue by somebody on the BB soon. > > Zhijie > > > > *From:* Jacob Keller <j-kell...@fsm.northwestern.edu> > *Sent:* Friday, February 15, 2013 2:44 PM > *To:* CCP4BB@JISCMAIL.AC.UK > *Subject:* [ccp4bb] Sighting of Protein Crystals in Vivo?! > > Dear Crystallographers, > > I was looking at some live, control HEK cells expressing just eGFP, and to > my great surprise, saw littered across the dish what appeared to be small > fluorescent needles (see attached--sorry about the size, but it's only ~1MB > total.) Can these possibly be fortuitous protein crystals? They were too > small to mount I think, and for what it's worth, parallel-transfected HeLa > cells did not have these things. But, some needles could be seen in the DIC > images as well, and the needles were only fluorescent with GFP filter sets, > and not CFP, YFP, or texas red filters. I thought of whale myoglobin > crystallizing on the decks of ships, but never thought I would see this.... > > Jacob > > -- > ******************************************* > Jacob Pearson Keller, PhD > Postdoctoral Associate > HHMI Janelia Farms Research Campus > email: j-kell...@northwestern.edu > ******************************************* >
