Structural highlights
FunctionC3SE17_ECOLX 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.[ARBA:ARBA00025375][HAMAP-Rule:MF_00475] Publication Abstract from PubMedThe crystal structures of domain-swapped tryptophan repressor (TrpR) variant Val58Ile before and after soaking with the physiological ligand L-tryptophan (L-Trp) indicate that L-Trp occupies the same location in the domain-swapped form as in native dimeric TrpR and makes equivalent residue contacts. This result is unexpected because the ligand binding-site residues arise from three separate polypeptide chains in the domain-swapped form. This work represents the first published structure of a domain-swapped form of TrpR with L-Trp bound. The presented structures also show that the protein amino-terminus, whether or not it bears a disordered extension of about 20 residues, is accessible in the large solvent channels of the domain-swapped crystal form, as in the structures reported previously in this form for TrpR without N-terminal extensions. These findings inspire the exploration of L-Trp analogs and N-terminal modifications as labels to orient guest proteins that cannot otherwise be crystallized in the solvent channels of crystalline domain-swapped TrpR hosts for potential diffraction analysis. Crystal structures of Val58Ile tryptophan repressor in a domain-swapped array in the presence and absence of L-tryptophan.,Sprenger J, Lawson CL, von Wachenfeldt C, Lo Leggio L, Carey J Acta Crystallogr F Struct Biol Commun. 2021 Jul 1;77(Pt 7):215-225. doi:, 10.1107/S2053230X21006142. Epub 2021 Jul 30. PMID:34196612[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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