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Title:Moessbauer Study of Reduced Putidaredoxin in Zero and Intermediate Applied Fields
Author(s):Valentine, Mark
Department / Program:Physics
Discipline:Physics
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Mathematics
Physics, Molecular
Biophysics, General
Abstract:An ('57)Fe Mossbauer investigation of the reduced (S = 1/2) active center of the redox and effector protein, putidaredoxin, is reported. Putidaredoxin is a prototype of a 2Fe-2S protein; it functions as an electron shuttle in a bacterial enzyme system. Several 2Fe-2S proteins, including putidaredoxin, have already been subjected to numerous Mossbauer and magnetic resonance studies, but current understanding of the active center is still very incomplete, and the mechanism of electron transfer is not known.
Previous Mossbauer experiments on reduced putidaredoxin, as on most Kramers systems, were restricted to the applied field range .01 - 4T. The intermediate field region 0 - .01T is included here, and a primary goal of this work is to demonstrate the feasibility of those experiments. The analysis of zero field spectra differs from that in applied fields in the following respects: (i) The spectra consist of 64 discrete lines. (ii) The average over all molecular orientations is done explicitly, not numerically. (iii) No generality is lost by taking the magnetic hyperfine terms for both sites to be symmetric and in their principal axis systems. (iv) The spectra are sensitive to weak coupling of S with nearby nuclear moments that become negligible as the applied field is increased.
Skew-symmetric contributions to the magnetic hyperfine and electronic Zeeman interactions are often ignored in the literature without justification. Either g or A can be symmetrized by an S transformation, but both g and A can be simultaneously symmetrized if and only if the invariants
(DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI)
are equal.
Issue Date:1983
Type:Text
Language:English
Description:151 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1983.
URI:http://hdl.handle.net/2142/77356
Other Identifier(s):(UMI)AAI8324664
Date Available in IDEALS:2015-05-13
Date Deposited:1983


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