Source:http://linkedlifedata.com/resource/pubmed/id/15654077
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
12
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pubmed:dateCreated |
2005-3-21
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pubmed:databankReference | |
pubmed:abstractText |
The solution structure of trimeric Escherichia coli enzyme IIA(Chb) (34 kDa), a component of the N,N'-diacetylchitobiose/lactose branch of the phosphotransferase signal transduction system, has been determined by NMR spectroscopy. Backbone residual dipolar couplings were used to provide long range orientational restraints, and long range (|i - j| > or = 5 residues) nuclear Overhauser enhancement restraints were derived exclusively from samples in which at least one subunit was 15N/13C/2H/(Val-Leu-Ile)-methyl-protonated. Each subunit consists of a three-helix bundle. Hydrophobic residues lining helix 3 of each subunit are largely responsible for the formation of a parallel coiled-coil trimer. The active site histidines (His-89 from each subunit) are located in three symmetrically placed deep crevices located at the interface of two adjacent subunits (A and C, C and B, and B and A). Partially shielded from bulk solvent, structural modeling suggests that phosphorylated His-89 is stabilized by electrostatic interactions with the side chains of His-93 from the same subunit and Gln-91 from the adjacent subunit. Comparison with the x-ray structure of Lactobacillus lactis IIA(Lac) reveals some substantial structural differences, particularly in regard to helix 3, which exhibits a 40 degrees kink in IIA(Lac) versus a 7 degrees bend in IIA(Chb). This is associated with the presence of an unusually large (230-angstroms3) buried hydrophobic cavity at the trimer interface in IIA(Lac) that is reduced to only 45 angstroms3) in IIA(Chb).
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Disaccharides,
http://linkedlifedata.com/resource/pubmed/chemical/Escherichia coli Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Phosphotransferases,
http://linkedlifedata.com/resource/pubmed/chemical/Solutions,
http://linkedlifedata.com/resource/pubmed/chemical/chitobiose
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pubmed:status |
MEDLINE
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pubmed:month |
Mar
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pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
25
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pubmed:volume |
280
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
11770-80
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:15654077-Amino Acid Sequence,
pubmed-meshheading:15654077-Binding Sites,
pubmed-meshheading:15654077-Disaccharides,
pubmed-meshheading:15654077-Escherichia coli,
pubmed-meshheading:15654077-Escherichia coli Proteins,
pubmed-meshheading:15654077-Light,
pubmed-meshheading:15654077-Magnetic Resonance Spectroscopy,
pubmed-meshheading:15654077-Molecular Sequence Data,
pubmed-meshheading:15654077-Phosphotransferases,
pubmed-meshheading:15654077-Scattering, Radiation,
pubmed-meshheading:15654077-Solutions
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pubmed:year |
2005
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pubmed:articleTitle |
Solution structure of enzyme IIA(Chitobiose) from the N,N'-diacetylchitobiose branch of the Escherichia coli phosphotransferase system.
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pubmed:affiliation |
Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-0520, USA.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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