Tris-sulfate might be acceptable for studies in the presence of
magnesium ion. Na-MES is tolerable at low concentrations and shorter
path lengths if a cutoff of 190-200 nm or so is acceptable. Chloride is
indeed problematic in the far UV.
_______________________________________
Roger S. Rowlett
Gordon & Dorothy Kline Professor
Department of Chemistry
Colgate University
13 Oak Drive
Hamilton, NY 13346
tel: (315)-228-7245
ofc: (315)-228-7395
fax: (315)-228-7935
email: rrowl...@colgate.edu
On 3/20/2013 9:32 AM, Vitali Stanevich wrote:
Harsh,
This article describes common buffers for CD on page 2:
http://www.ncbi.nlm.nih.gov/pubmed/17406547
Or this article on page 8:
http://www.ncbi.nlm.nih.gov/pubmed/16027053
It seems like phosphate is the best, because it has low absorption at
180-200nm region. From organic buffers Tris/H2SO4 seems to the the
best. As I remember, Cl absorbs a lot in that UV region.
Vitali
On Wed, Mar 20, 2013 at 1:59 AM, Harsh Bansia <spideysp...@gmail.com
<mailto:spideysp...@gmail.com>> wrote:
Sorry for a simple and non-CCP4 question.
I have determined the structures of three different mutants of a
thermostable protein by X-ray crystallography method. I feel that
Mg2+ has a role in protein stability.
So I want to perform a thermal denaturation study by CD
spectroscopy both in presence and absence of Mg2+ ion.
In this regards, what should be the suitable buffer for CD
studies? May I use PBS buffer ? Since phosphate sequester divalent
cations like Mg2+. Is it advisable to use PBS buffer. If so, what
is maximum concentration of Mg2+ ion that can be used say e.g. 5
mM? My protein was in Tris buffer and lyophilized and have
theoretical pI =4.56 and maximum activity at pH 8.4.
Thanking you in advances,
harsh
