TY - JOUR
T1 - Neutral additives enhance the metal-chelate affinity adsorption of nucleic acids
T2 - Role of water activity
AU - Potty, Ajish S.R.
AU - Fu, Joseph Y.
AU - Balan, Sindhu
AU - Haymore, Barry L.
AU - Hill, David J.
AU - Fox, George E.
AU - Willson, Richard C.
N1 - Funding Information:
This research was funded in part by grants from NASA (grant NNJ04HF43G to R.C.W. and G.E.F.), NSF (grant CTS-0004544 to RCW) and the Robert A. Welch Foundation (grants E-1264 to R.C.W. and E-1270 to G.E.F.).
Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2006/5/19
Y1 - 2006/5/19
N2 - Immobilized metal-chelate affinity chromatography has been widely used in the purification of proteins, and we have recently found that it can also be applied to purification of nucleic acids through interactions involving exposed bases, especially purines. Here we report that the inclusion of moderate quantities of neutral solutes in the buffer substantially enhances the binding affinity of nucleic acids for immobilized metal-chelate affinity adsorbents. Addition of 20% (v/v) of solutes such as ethanol, methanol, isopropanol, n-propanol, and dimethyl sulfoxide enhances the initial affinity of binding of total yeast RNA by 4.4-, 3.8-, 3.7-, 3.0-, and 2.8-fold, respectively for Cu(II)-iminodiacetic acid (IDA) agarose adsorbent, and the weaker adsorption by Cu(II)-nitrilotriacetic acid (NTA) agarose was even more strongly enhanced. The adsorption affinities of the smaller oligodeoxynucleotide molecules A20, G20, C20 and T20 also increase with the addition of ethanol, suggesting that the effect is not significantly mediated by conformational changes. Binding enhancement generally correlates with reduction of water activity by the various solutes, as predicted by several models of solution thermodynamics, consistent with an entropic contribution by displacement of waters from the metal-chelate. Interestingly, the enhancement was not seen with the proteins bovine serum albumin and lysozyme.
AB - Immobilized metal-chelate affinity chromatography has been widely used in the purification of proteins, and we have recently found that it can also be applied to purification of nucleic acids through interactions involving exposed bases, especially purines. Here we report that the inclusion of moderate quantities of neutral solutes in the buffer substantially enhances the binding affinity of nucleic acids for immobilized metal-chelate affinity adsorbents. Addition of 20% (v/v) of solutes such as ethanol, methanol, isopropanol, n-propanol, and dimethyl sulfoxide enhances the initial affinity of binding of total yeast RNA by 4.4-, 3.8-, 3.7-, 3.0-, and 2.8-fold, respectively for Cu(II)-iminodiacetic acid (IDA) agarose adsorbent, and the weaker adsorption by Cu(II)-nitrilotriacetic acid (NTA) agarose was even more strongly enhanced. The adsorption affinities of the smaller oligodeoxynucleotide molecules A20, G20, C20 and T20 also increase with the addition of ethanol, suggesting that the effect is not significantly mediated by conformational changes. Binding enhancement generally correlates with reduction of water activity by the various solutes, as predicted by several models of solution thermodynamics, consistent with an entropic contribution by displacement of waters from the metal-chelate. Interestingly, the enhancement was not seen with the proteins bovine serum albumin and lysozyme.
KW - Adsorption
KW - DNA
KW - Ethanol
KW - IMAC
KW - Isotherm
KW - Metal-chelate affinity
KW - Neutral solutes
KW - RNA
UR - http://www.scopus.com/inward/record.url?scp=33646482584&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33646482584&partnerID=8YFLogxK
U2 - 10.1016/j.chroma.2006.02.077
DO - 10.1016/j.chroma.2006.02.077
M3 - Article
C2 - 16600263
AN - SCOPUS:33646482584
VL - 1115
SP - 88
EP - 92
JO - Journal of Chromatography A
JF - Journal of Chromatography A
SN - 0021-9673
IS - 1-2
ER -