Register to reply

Please help me interpret my protein chemical-denaturation graphs

by Dave_Vader
Tags: protein
Share this thread:
Dave_Vader
#1
Nov5-13, 02:25 PM
P: 2
Hi,
I'm working with proteins at IISc (Bangalore).
I'm characterising a 226-residue long protein of an unknown fold.
I'm trying to use CD spectroscopy to calculate the ΔG for protein unfolding.
I have used both GuHCl (0M - 3M) and Urea (0M - 4M) chemical gradients.

Here are the graphs: http://oi41.tinypic.com/2rtpk.jpg
Please note that I drew the red lines on MS paint. No curve-fitting here.

Ideally, I should get a nice, smooth sigmoidal curve.
However, in both cases, I'm getting an initial 'dip' in CD values.
This would indicate that the protein is folding BETTER under slight denaturing conditions.
These results are reproducible. I've run 3 replicates for each graph.

Have you seen chemical denaturation curves like these before?
If so, how do you interpret such data? Please post links.

Other details:
-Protein is pretty soluble (purified to 5-10 mg/ml).
-Shows alpha-beta CD spectrum (190-250 nm range).
-It's Tm is 45C (this graph is a smooth sigmoid).

Thanks a lot.
Phys.Org News Partner Biology news on Phys.org
Geneticists offer clues to better rice, tomato crops
Designer potatoes on the menu to boost consumption
Giant anteaters kill two hunters in Brazil

Register to reply

Related Discussions
Denaturation and Peptide Bonds Biology, Chemistry & Other Homework 2
Interpret Voltage-time graphs to relate the ouput voltage of a piezoelectric crystal Electrical Engineering 7
How to interpret integrals of graphs Calculus & Beyond Homework 3
Protein - Protein DOCKING ... Computing & Technology 0
Protein of life, protein of death Biology 3