MOSSBAUER STUDIES OF LOW-SPIN FERRIC PROTEINS
MOSSBAUER STUDIES OF LOW-SPIN FERRIC PROTEINS
批准号:
3438502
负责人:
CHARLES E SCHULZ
金额:
$5.67万
依托单位:
依托单位国家:
美国
项目类别:
财政年份:
1987
资助国家:
美国
项目状态:
已结题
起止时间:
1987-07-01 至 1990-12-30
中文摘要
低自旋铁中铁位的物理性质
英文摘要
The physical characterization of the iron site in low-spin ferric
heme proteins is very important in working toward an
understanding of the structure-function relationships in these
systems. The proposed research will investigate two aspects of
the protein structure: i) how the ligand field of the iron is
perturbed by slight changes in the amino acid sequence and
structure of the protein, and ii) the temperature dependence of
the spin-lattice relaxation and how it varies with changes in the
solvent. The first line of investigation is made possible by the
expression of a synthetic rat hepatic cytochrome b5 gene in E.
coli, where it is expressed in extremely large quantities, up to
20% of total cell protein. Specific modifications can be made in
the cytochrome by cartridge mutagenesis. These modified
proteins will be studied by EPR and Mossbauer spectroscopy, and
the spectra will be parametrized by a S=1/2 Spin Hamiltonian,
which can then be used as the basis for a ligand field
characterization of the iron site.
The temperature dependence of the Mossbauer spectra will serve
as a further test of the fractal model for protein vibrational
modes. EPR measurements of various heme and iron-sulfur
proteins indicate that the phonon density of states in these
systems is consistent with a model in which the protein has a
fractional dimension of 1.1-1.8. These measurements were made
for temperatures below 12K. Mossbauer spectroscopy is an ideal
method to extend these studies to the temperature range 15K-
200K because 1) the integrated intensity of the Mossbauer
spectrum is not as strong a function of temperature as is EPR;
and, 2) EPR measurements indicate that the fluctuation rates for
these temperatures should be in the range to which Mossbauer
spectra are sensitive. We propose to first study myoglobin azide
and the effects of the solvent on its fractional dimension, with
the work later to be extended to the Horseradish peroxidase
cyanide complex, cytochrome b5, and small heme model
compounds.
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MOSSBAUER STUDIES OF HEME MODELS AND MUTANT MYOGLOBINS
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批准号:2185981
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项目类别:
-
资助金额:$4.72万
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财政年份:1992
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负责人:CHARLES E SCHULZ
-
依托单位:
MOSSBAUER STUDIES OF HEME MODELS AND MUTANT MYOGLOBINS
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批准号:2185980
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项目类别:
-
资助金额:$3.92万
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财政年份:1992
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负责人:CHARLES E SCHULZ
-
依托单位:
MOSSBAUER STUDIES OF HEME MODELS AND MUTANT MYOGLOBINS
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批准号:3307971
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项目类别:
-
资助金额:$11.06万
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财政年份:1992
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负责人:CHARLES E SCHULZ
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依托单位: