INFLUENCES OF MACROMOLECULAR CROWDING ON BIOCHEMICAL SYSTEMS
INFLUENCES OF MACROMOLECULAR CROWDING ON BIOCHEMICAL SYSTEMS
批准号:
6161965
负责人:
S B ZIMMERMAN
金额:
$0.0万
依托单位国家:
美国
项目类别:
财政年份:
--
资助国家:
美国
项目状态:
未结题
起止时间:
至
中文摘要
大肠杆菌的类核结构在很大程度上是未知的。
英文摘要
The structure of the nucleoid of Escherichia coli is largely unknown.
As an approach to this long-standing problem, we have extensively
characterized nucleoid preparations that were isolated from E. coli
under relatively non-denaturing conditions (spermidine nucleoids,
Kornberg et al.) The isolated nucleoids were greatly stabilized by
macromolecular crowding, consistent with earlier suggestions of an in
vivo compacting effect of the highly concentrated, surrounding bacterial
cytoplasm (manuscripts in press). A relatively simple pattern of
proteins was released from the isolated nucleoids upon digestion with
pancreatic DNase. Three small, DNA-binding proteins (HU, H-NS, and Fis)
and residual lysozyme from the cell lysis procedure account for half of
the protein released, with RNA polymerase accounting for much of the
remainder. The proteins have been identified by electrophoretic
criteria and, in the case of H-NS and Fis, by their N-terminal amino
acid sequences. Extraction of isolated nucleoids with elevated salt
concentrations under crowded, stabilizing conditions efficiently removes
two of the prominent proteins (HU and lysozyme), yet the compact form
of the nucleoids is retained. These extracted nucleoids continue to
maintain their compact form upon reisolation into the initial uncrowded
low-salt medium, indicating that HU, the most common "histone-like"
protein of E. coli, is not a necessary component for maintaining
compaction in these preparations. Exposure of the isolated nucleoids
to intermediate concentrations of urea or NaCl results in the unfolding
of the DNA into long streamers, as seen by light microscopy. The DNA
undergoes characteristic changes in sedimentation properties as the urea
or NaCl strips off increasing amounts of the nucleoid proteins. There
is considerable hysteresis with respect to the concentrations of NaCl
required for the removal of several proteins, notably Fis and H-NS,
possibly indicating the existence of a salt-labile structure involving
these proteins. Our current focus is in validating and defining this
structure and distinguishing it from the complexes formed simply due to
the affinity between these proteins and the DNA.
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INFLUENCES OF MACROMOLECULAR CROWDING ON BIOCHEMICAL SYSTEMS
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批准号:2573111
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项目类别:
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资助金额:$0.0万
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财政年份:--
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负责人:S B ZIMMERMAN
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依托单位:
INFLUENCES OF MACROMOLECULAR CROWDING ON BIOCHEMICAL SYSTEMS
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批准号:5201983
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项目类别:
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资助金额:$0.0万
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财政年份:--
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负责人:S B ZIMMERMAN
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依托单位:
INFLUENCES OF MACROMOLECULAR CROWDING ON BIOCHEMICAL SYSTEMS
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批准号:3940872
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项目类别:
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资助金额:$0.0万
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财政年份:--
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负责人:S B ZIMMERMAN
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依托单位:
INFLUENCES OF MACROMOLECULAR CROWDING ON BIOCHEMICAL SYSTEMS
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批准号:3854953
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项目类别:
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资助金额:$0.0万
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财政年份:--
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负责人:S B ZIMMERMAN
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依托单位:
INFLUENCES OF MACROMOLECULAR CROWDING ON BIOCHEMICAL SYSTEMS
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批准号:3776440
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项目类别:
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资助金额:$0.0万
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财政年份:--
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负责人:S B ZIMMERMAN
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依托单位:
INFLUENCES OF MACROMOLECULAR CROWDING ON BIOCHEMICAL SYSTEMS
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批准号:3754321
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项目类别:
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资助金额:$0.0万
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财政年份:--
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负责人:S B ZIMMERMAN
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依托单位:
INFLUENCES OF MACROMOLECULAR CROWDING ON BIOCHEMICAL SYSTEMS
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批准号:4689922
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项目类别:
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资助金额:$0.0万
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财政年份:--
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负责人:S B ZIMMERMAN
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依托单位:
INFLUENCES OF MACROMOLECULAR CROWDING ON BIOCHEMICAL SYSTEMS
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批准号:3876006
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项目类别:
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资助金额:$0.0万
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财政年份:--
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负责人:S B ZIMMERMAN
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依托单位:
INFLUENCES OF MACROMOLECULAR CROWDING ON BIOCHEMICAL SYSTEMS
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批准号:3964707
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项目类别:
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资助金额:$0.0万
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财政年份:--
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负责人:S B ZIMMERMAN
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依托单位:
INFLUENCES OF MACROMOLECULAR CROWDING ON BIOCHEMICAL SYSTEMS
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批准号:3917964
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项目类别:
-
资助金额:$0.0万
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财政年份:--
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负责人:S B ZIMMERMAN
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依托单位:
INFLUENCES OF MACROMOLECULAR CROWDING ON BIOCHEMICAL SYSTEMS
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批准号:3840001
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项目类别:
-
资助金额:$0.0万
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财政年份:--
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负责人:S B ZIMMERMAN
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依托单位:
海外基金