Abstract
Linear dichroism provides information on the orientation of chromophores part of, or bound to, an orientable molecule such as DNA. For molecular alignment induced by hydrodynamic shear, the principal axes orthogonal to the direction of alignment are not equivalent. Thus, the magnitude of the flow-induced change in absorption for light polarized parallel to the direction of flow can be more than a factor of two greater than the corresponding change for light polarized perpendicular to both that direction and the shear axis. The ratio of the two flow-induced changes in absorption, the dichroic increment ratio, is characterized using the orthogonal orientation model, which assumes that each absorbing unit is aligned parallel to one of the principal axes of the apparatus. The absorption of the alienable molecules is characterized by components parallel and perpendicular to the orientable axis of the molecule. The dichroic increment ratio indicates that for the alignment of DNA in rectangular flow cells, average alignment is not uniaxial, but for higher shear, as produced in a Couette cell, it can be. The results from the simple model are identical to tensor models for typical experimental configurations. Approaches for measuring the dichroic increment ratio with modern dichrometers are discussed.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 24-31 |
| Number of pages | 8 |
| Journal | Analytical Biochemistry |
| Volume | 523 |
| DOIs | |
| State | Published - Apr 15 2017 |
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Keywords
- Couette cell
- DNA ligands
- Dichroic increment ratio
- Equivalent orthogonal orientation
- Photoelastic modulator
- Polarized absorption
- Scalene ellipsoid
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Molecular Biology
- Cell Biology
Cite this
Linear dichroism of DNA : Characterization of the orientation distribution function caused by hydrodynamic shear. / Sutherland, John C.
In: Analytical Biochemistry, Vol. 523, 15.04.2017, p. 24-31.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Linear dichroism of DNA
T2 - Characterization of the orientation distribution function caused by hydrodynamic shear
AU - Sutherland, John C.
PY - 2017/4/15
Y1 - 2017/4/15
N2 - Linear dichroism provides information on the orientation of chromophores part of, or bound to, an orientable molecule such as DNA. For molecular alignment induced by hydrodynamic shear, the principal axes orthogonal to the direction of alignment are not equivalent. Thus, the magnitude of the flow-induced change in absorption for light polarized parallel to the direction of flow can be more than a factor of two greater than the corresponding change for light polarized perpendicular to both that direction and the shear axis. The ratio of the two flow-induced changes in absorption, the dichroic increment ratio, is characterized using the orthogonal orientation model, which assumes that each absorbing unit is aligned parallel to one of the principal axes of the apparatus. The absorption of the alienable molecules is characterized by components parallel and perpendicular to the orientable axis of the molecule. The dichroic increment ratio indicates that for the alignment of DNA in rectangular flow cells, average alignment is not uniaxial, but for higher shear, as produced in a Couette cell, it can be. The results from the simple model are identical to tensor models for typical experimental configurations. Approaches for measuring the dichroic increment ratio with modern dichrometers are discussed.
AB - Linear dichroism provides information on the orientation of chromophores part of, or bound to, an orientable molecule such as DNA. For molecular alignment induced by hydrodynamic shear, the principal axes orthogonal to the direction of alignment are not equivalent. Thus, the magnitude of the flow-induced change in absorption for light polarized parallel to the direction of flow can be more than a factor of two greater than the corresponding change for light polarized perpendicular to both that direction and the shear axis. The ratio of the two flow-induced changes in absorption, the dichroic increment ratio, is characterized using the orthogonal orientation model, which assumes that each absorbing unit is aligned parallel to one of the principal axes of the apparatus. The absorption of the alienable molecules is characterized by components parallel and perpendicular to the orientable axis of the molecule. The dichroic increment ratio indicates that for the alignment of DNA in rectangular flow cells, average alignment is not uniaxial, but for higher shear, as produced in a Couette cell, it can be. The results from the simple model are identical to tensor models for typical experimental configurations. Approaches for measuring the dichroic increment ratio with modern dichrometers are discussed.
KW - Couette cell
KW - DNA ligands
KW - Dichroic increment ratio
KW - Equivalent orthogonal orientation
KW - Photoelastic modulator
KW - Polarized absorption
KW - Scalene ellipsoid
UR - http://www.scopus.com/inward/record.url?scp=85012237766&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85012237766&partnerID=8YFLogxK
U2 - 10.1016/j.ab.2017.01.016
DO - 10.1016/j.ab.2017.01.016
M3 - Article
C2 - 28115171
AN - SCOPUS:85012237766
VL - 523
SP - 24
EP - 31
JO - Analytical Biochemistry
JF - Analytical Biochemistry
SN - 0003-2697
ER -