Engi Hassaan

9 Questions 10 Answers 0 Followers

Questions related from Engi Hassaan

What is a self intensity test in STD NMR?

Some papers report performing a "STD self intensity" test to check the aggregation of compounds in STD NMR. Can anyone please elaborate how such a test is performed?

08 August 2019 6,882 2 View

What is the correct equation to use when weighing the different chemical shifts of 1H and 15N nuclei in SOFAST HMQC spectra?

I read in the attached paper the equation for HSQC spectra (equation 8). What about HMQC? I cannot find a reference online. Thanks!

05 May 2019 9,828 2 View

Is there a program I can use to align lattice constants of a protein crystal?

I have 2 protein crystal structures and I would like to align their origins so I can then generate the crystal packing of each and compare them.

03 March 2019 1,039 2 View

After my TEV cleavage site I have a remaining 'am' sequence. Where does this come from?

I am purifying a protein with a his tag. The TEV cleavage site I read is composed of ENLYFQG, and this G remains after cleavage. What I found to also remain is an 'am'. It is before the first...

10 October 2017 1,493 2 View

I stored my lysate at 4°C, can I still use it or toss it out?

I have lysed my e. coli cells (after adding protease inhibitors to the lysis buffer) and freezed the lysate. I then unfroze with the intent of purifying my protein , however due to column...

07 July 2017 4,431 7 View

Has anyone tried to add IPTG to auto inducing media like ZYM? Did you notice an increase in protien expression or is it pointless?

I express using BL21 DE3 e-coli cells and use the ZYM 5052 media. Some colleagues who also use this media have suggested adding IPTG to increase the protein expression. Would that make any sense...

07 July 2017 6,368 3 View

Effect of 1000 folds antibiotic addition to e. coli culture media?

I usually add 100ug/ml of kanamycin to my ZYM culture media. I accidently in a moment of fatigue added the entire 100mg/ml stock to one of my batches! What effect will this have on the cell growth...

08 August 2016 5,001 3 View

My DNA plasmid purification yielded a 260/280 ratio of 2.15. Why?

After following the exact protocol of the NucleoSpin Plasmid purification kit, I measured the concentration to find the 260/280 ratio 2.15! Any idea what could have gone wrong and how can I fix this?

05 May 2016 2,871 4 View

Can I re-induce protein expression after storage at 4 degrees Celsius?

I was expressing protein in E coli cells at 37 degrees and the OD was 1. I had to store the culture over 3 nights, so I stored it at 4 degrees to prevent over expression. After the 3 nights I...

05 May 2016 3,246 4 View