1TLF: Lac repressor

Unprecedented quaternary structure of E. Coli lac repressor core tetramer: implications for DNA looping. Determined by X-ray diffraction at 2.6 Å resolution. Released 31 Jul 1995.

Method

X-ray diffraction

Resolution

2.6 Å

Organism

Escherichia coli

Chains

4

Atoms

8,924

Mol. weight

130.49 kDa

Ligands

IPT, EMC

Released

31 Jul 1995

Explore 1TLF in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

1TLF contains 44 α-helices and 63 β-strands across 4 chains. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.

Chain A: 12 helices, 14 β-strands

Molecules and chains

>1TLF_1 LAC REPRESSOR (chains A, B, C, D)
QSLLIGVATSSLALHAPSQIVAAIKSRADQLGASVVVSMVERSGVEACKAAVHNLLAQRV
SGLIINYPLDDQDAIAVEAACTNVPALFLDVSDQTPINSIIFSHEDGTRLGVEHLVALGH
QQIALLAGPLSSVSARLRLAGWHKYLTRNQIQPIAEREGDWSAMSGFQQTMQMLNEGIVP
TAMLVANDQMALGAMRAITESGLRVGADISVVGYDDTEDSSCYIPPLTTIKQDFRLLGQT
SVDRLLQLSQGQAVKGNQLLPVSLVKRKTTLAPNTQTASPRALADSLMQLARQVSRLESG
Q

Ligands and cofactors

Primary citation

Crystal structure of lac repressor core tetramer and its implications for DNA looping. Friedman, A.M., Fischmann, T.O., Steitz, T.A. Science (1995) 268:1721-1727. PubMed

Related structures

Other PDB entries of the same protein (UniProt P03023 (AlphaFold model), which also has an AlphaFold model), best resolution first:

• 8GOH 1.1 Å, Homotetramic Antiparallel Coiled-Coil of 23-residues LacI C-terminal tetramerization helix
• 1JYE 1.7 Å, Structure of a Dimeric Lac Repressor with C-terminal Deletion and K84L Substitution
• 2P9H 2.0 Å, High resolution structure of the Lactose Repressor bound to IPTG
• 3EDC 2.1 Å, Crystal Structure of a 1.6-hexanediol Bound Tetrameric Form of Escherichia coli…
• 1EFA 2.6 Å, Crystal structure of the lac repressor dimer bound to operator and the anti-inducer onpf
• 1LBI 2.7 Å, Lac repressor
• 4RZS 2.71 Å, Lac repressor engineered to bind sucralose, unliganded tetramer
• 1JYF 3.0 Å, Structure of the Dimeric Lac Repressor with an 11-residue C-terminal Deletion.
• 4RZT 3.1 Å, Lac repressor engineered to bind sucralose, sucralose-bound tetramer
• 1LBH 3.2 Å, Intact lactose operon repressor with gratuitous inducer iptg
• 2PAF 3.5 Å, Crystal Structure of the Lactose Repressor bound to anti-inducer ONPF in induced state
• 2PE5 3.5 Å, Crystal Structure of the Lac Repressor bound to ONPG in repressed state

Browse structure collections

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