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Questions related from Sam Tang
I saw that most Delta (Tm) being positive upon ligand binding to a protein. But is it ever possible that Delta (Tm) goes the other way? If yes, under what circumstances will it be negative?
13 June 2022 9,849 0 View
When I tested the toxicity of my inhibitor on MDCK, all the cells die at 100 uM. However interestingly at 200 uM or 300 uM the MTT values go up back to half the negative control! Any idea what's...
19 December 2021 1,384 1 View
I am performing a TSA to investigate binding of a ligand to the protein by performing a serial dilution of ligand against same conc. of protein (~2uM). Interestingly at low ligand conc the...
03 August 2020 3,447 1 View
I compared my wild-type protein and a truncation towards binding of RNA by microscale thermophoresis. The truncation shows a V-shape curve resembling biphasic binding. Theoretically the truncation...
05 April 2019 5,593 0 View
Hi I have been struggling with the purification of a GFP-tagged peptide from E.coli. It seems that the peptide degrades and left GFP alone once the cell is lysed. Looking at the sequence there...
24 January 2019 2,810 7 View
I am carrying our an experiment to characterize the biological effect of three mutant proteins compared to the wild-type control. I carry out triplicate experiment each time for the four proteins...
17 August 2018 6,273 3 View
Hi I mixed Tris HCl, EDTA, NaCl and deoxycholate 0.5% to make up a 1x RIPA buffer stock. After overnight in fridge, I found that my buffer becomes gel-like! It literally form a 'jelly' in my...
09 July 2018 212 4 View
Dear all I wish to stain the nucleolus of A549 for confocal microscopy but I don't want a dye which stains the RNA because the protein I am monitoring is RNA-binding, meaning that a RNA-targeting...
24 September 2017 2,228 4 View
Hi I recently processed a x-ray diffraction data set to 2.5 A for my protein complex. After data reduction with imosflm and Aimless, it turns out the Rmerge is 0.000 (see below). Also, the mean...
30 April 2016 5,280 1 View
Hi In a recent structure we have recently obtained by x-ray diffraction and solved by MR, we actually see obviously positive density for which we are quite confident to account for our ligand....
28 April 2016 1,003 3 View
A recent structure at 2.5A was solved by our group. We observed that at the proposed peptide binding site extra densities (after Refmac) are present on 2Fo-Fc (1 sigma, same below), but...
24 March 2016 4,402 2 View
I am solving a structure which has a space group P41/P43. I now model a structure into the map and the two protomers wrap along each other like a helix! So it is now clear to be P43. A problem I...
13 October 2015 8,399 3 View
The radiation damage was obvious because when the diffraction goes on there were less and less spots and the resolution dropped. I was able to scale the data set in HKL2000 but I wonder if any...
11 October 2015 156 4 View
I am trying to set up a direct FRET experiment in Beas2B cells to investigate the interaction between two proteins A and B. I set up three dishes, namely CFP-A, YFP-B (controls) and CFP-A +...
02 March 2015 9,970 3 View
Hi, I am having a 4kDa peptide expressed from E. coli and purified. I would like to quantify the concentration before I use it for crystallization experiment. Unfortunately, it does not contain...
31 December 2014 2,304 11 View
Hello, I tried to refine a model from xray data using phenix.refine including a Ramachandran_restraints = True command line. It however turns out with an 'Unknown command line parameter...
25 November 2014 3,535 1 View
