1j5g: Difference between revisions
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==KNOWLEDGE BASED MODEL OF A LAMBDA REPRESSOR TETRAMER (TWO DIMERS) BOUND TO TWO ADJACENT OPERATOR SITES== | |||
<StructureSection load='1j5g' size='340' side='right' caption='[[1j5g]]' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1J5G FirstGlance]. <br> | |||
</td></tr><tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1j5g FirstGlance], [http://www.ebi.ac.uk/pdbsum/1j5g PDBsum]</span></td></tr> | |||
<table> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The circular dichroism spectra of three different purified carboxy terminal fragments 93-236, 112-236 and 132-236 of the bacteriophage lambda cI repressor have been measured and compared with those of the intact repressor and the amino terminal fragment 1-92. All three carboxy terminal fragments contain mostly beta-strands and loops, a minor helix content increasing with the size of the fragment, showing that the 93-131 region previously called a hinge is structured. Fourier transformed infrared spectra also showed that fragment 93-236 contains alpha-helices, alpha-sheets and turns but fragment 132-236 contains no detectable alpha-helix, only beta-sheets and turns. Papain is known to cleave the lambda repressor, but it is shown here that it cannot cleave the operator-bound repressor dimer. For the 132-236 fragment, both the wt and the SN228 mutant previously shown to be dimerization defective in the intact, gave similar dimerization properties as investigated by HPLC at 2 to 100 microM protein concentration, with a KD of 13.2 microM and 19.1 microM respectively. The papain cleavage for wt and SN228 proceed at equal rates for the first cleavage at 92-93; however, the subsequent cleavages are faster for SN228. The three Cys residues in the 132-236 fragment were found to be unreactive upon incubation with DTNB, indicating the thiol sulfur atoms are buried in the repressor carboxy terminal domain. Denaturation of the 132-236 fragment studied by tryptophan fluorescence shows two transitions centered at 1.5 M and 4.5 M of urea. | |||
Papain does not cleave operator-bound lambda repressor: structural characterization of the carboxy terminal domain and the hinge.,Ghosh K, Chattopadhyaya R J Biomol Struct Dyn. 2001 Feb;18(4):557-67. PMID:11245251<ref>PMID:11245251</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
== | |||
< | |||
[[Category: Chattopadhyaya, R]] | [[Category: Chattopadhyaya, R]] | ||
[[Category: Ghosh, K]] | [[Category: Ghosh, K]] | ||
Revision as of 13:40, 28 September 2014
KNOWLEDGE BASED MODEL OF A LAMBDA REPRESSOR TETRAMER (TWO DIMERS) BOUND TO TWO ADJACENT OPERATOR SITESKNOWLEDGE BASED MODEL OF A LAMBDA REPRESSOR TETRAMER (TWO DIMERS) BOUND TO TWO ADJACENT OPERATOR SITES
Structural highlights
Publication Abstract from PubMedThe circular dichroism spectra of three different purified carboxy terminal fragments 93-236, 112-236 and 132-236 of the bacteriophage lambda cI repressor have been measured and compared with those of the intact repressor and the amino terminal fragment 1-92. All three carboxy terminal fragments contain mostly beta-strands and loops, a minor helix content increasing with the size of the fragment, showing that the 93-131 region previously called a hinge is structured. Fourier transformed infrared spectra also showed that fragment 93-236 contains alpha-helices, alpha-sheets and turns but fragment 132-236 contains no detectable alpha-helix, only beta-sheets and turns. Papain is known to cleave the lambda repressor, but it is shown here that it cannot cleave the operator-bound repressor dimer. For the 132-236 fragment, both the wt and the SN228 mutant previously shown to be dimerization defective in the intact, gave similar dimerization properties as investigated by HPLC at 2 to 100 microM protein concentration, with a KD of 13.2 microM and 19.1 microM respectively. The papain cleavage for wt and SN228 proceed at equal rates for the first cleavage at 92-93; however, the subsequent cleavages are faster for SN228. The three Cys residues in the 132-236 fragment were found to be unreactive upon incubation with DTNB, indicating the thiol sulfur atoms are buried in the repressor carboxy terminal domain. Denaturation of the 132-236 fragment studied by tryptophan fluorescence shows two transitions centered at 1.5 M and 4.5 M of urea. Papain does not cleave operator-bound lambda repressor: structural characterization of the carboxy terminal domain and the hinge.,Ghosh K, Chattopadhyaya R J Biomol Struct Dyn. 2001 Feb;18(4):557-67. PMID:11245251[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References |
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