View source for 1j5g

{{Theoretical_model}}

==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 [https://proteopedia.org/fgij/fg.htm?mol=1J5G FirstGlance]. <br>
</td></tr><tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1j5g FirstGlance], [https://www.ebi.ac.uk/pdbsum/1j5g PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1j5g ProSAT]</span></td></tr>
</table>
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== 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&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1j5g" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Theoretical Model]]
[[Category: Large Structures]]
[[Category: Chattopadhyaya, R]]
[[Category: Ghosh, K]]