What are people's opinion on high vs low copy number for protein expression in E. coli?

05 June 2015 3,674 10 View

Protein-aptamer gel electrophoresis help, please??

Hi, I have problems with running gel electrophoresis. I have tried agarose gel electrophoresis and native PAGE. I have two proteins, which have molecular weights of ~30kDa and ~180kDa and two...

03 March 2021 4,275 4 View

Why are my bands weird in this Agarose gel?

Can someone please give me some possible things that could go wrong? Here is my recipe: 0.5g Agarose 50 mL of TAE 1x 1 uL ethyl bromide. Gel was run at 100V for 1 hour. The buffer used is also TAE.

01 March 2021 9,952 3 View

Why might my GFP tag be dissociating from my plasmid after transfection?

I have a set of stably transfected cell lines all transfected with plasmids containing GFP tags on the C terminus. During a western blot using anti-GFP antibody, one of my plasmids has dissociated...

01 March 2021 9,310 4 View

Precipitate after adding laemmli buffer to protein solution containing Potassium Acetate?

Hi, I am running a size exclusion chromatography experiment with a buffer containing Potassium Acetate as a salt. I analyse these fractions through SDS-PAGE. After boiling my SEC fractions in...

01 March 2021 2,622 3 View

What is the most suitable server for predicting protein structures in bacteria?

I have used the i-Tasser several times, however it has been unavailable for several days. I tried the swiss-model, but the output was not very pleasant due to the model used. Is there any other...

28 February 2021 4,521 3 View

Do you need the CMV enhancer before the CMV promotor for a proper function of CMV on the gene that follows?

I'm a student and I have to produce a cell line with a knockin for the NRF2 gene with GFP. I have to put a promotor in front of the GFP because the gene will be too far away from the promotor of...

28 February 2021 7,127 2 View

Are protein samples in SDS compatible with ELISA?

I have used an AllPrep DNA/RNA/Protein Mini Kit QIAGEN kit to extract RNA and protein from my samples. At the end of the protein purification, I resuspend my protein in 5% SDS. Will these samples...

28 February 2021 7,370 3 View

Why my agarose gel staining sometimes looks not homogenic but like gradient (see the figure)?

I am worried about this overexposure of the upper part of the gel in the picture. Is it possible that this is the result of too much concentration of ethidium bromide? Why is there such a big...

25 February 2021 8,140 3 View

How to replicate the well conditions of a crystal hit with 20%(w/v) isopropanol?

I had a crystal hit in a well with 0.1M HEPEs pH 7.5, 10%(w/v) PEG 4000, and 20%(w/v) isopropanol. Why is isopropanol in w/v here if it's just solvent? How do I recreate this well condition?

25 February 2021 9,761 1 View

Problem with ligating 2.8 kb insert into 8.5 kb plasmid?

I am trying to clone 2 copies of the same mammalian gene into the pSF-CMV-Ub-Puro Ascl (contains HindIII, KpnI and NheI cut sites) plasmid. This is what the final product is supposed to look like...

24 February 2021 6,310 3 View