2oz9
E. coli TRP holorepressor, orthorhombic crystal formE. coli TRP holorepressor, orthorhombic crystal form
Structural highlights
FunctionTRPR_ECOLI This protein is an aporepressor. When complexed with L-tryptophan it binds the operator region of the trp operon (5'-ACTAGT-'3') and prevents the initiation of transcription. The complex also regulates trp repressor biosynthesis by binding to its regulatory region. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedAn 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. 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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