2oz9 | pdb_00002oz9
E. coli TRP holorepressor, orthorhombic crystal form
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Overview
An orthorhombic crystal form of trp repressor (aporepressor plus L-tryptophan ligand) was solved by molecular replacement, refined to 1.65 A resolution, and compared to the structure of the repressor in trigonal crystals. Even though these two crystal forms of repressor were grown under identical conditions, the refined structures have distinctly different conformations of the DNA-binding domains. Unlike the repressor/aporepressor structural transition, the conformational shift is not caused by the binding or loss of the L-tryptophan ligand. We conclude that while L-tryptophan binding is essential for forming a specific complex with trp operator DNA, the corepressor ligand does not lock the repressor into a single conformation that is complementary to the operator. This flexibility may be required by the various binding modes proposed for trp repressor in its search for and adherence to its three different operator sites.
About this Structure
2OZ9 is a Single protein structure of sequence from Escherichia coli with NA, SO4 and TRP as ligands. This structure supersedes the now removed PDB entry 2WRP. Full crystallographic information is available from OCA.
Reference
Flexibility of the DNA-binding domains of trp repressor., Lawson CL, Zhang RG, Schevitz RW, Otwinowski Z, Joachimiak A, Sigler PB, Proteins. 1988;3(1):18-31. PMID:3375234
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