HTH_LACIhelix_turn _helix lactose operon repressor
|SMART accession number:||SM00354|
|Interpro abstract (IPR000843):||Numerous bacterial transcription regulatory proteins bind DNA via a helix-turn-helix (HTH) motif. These proteins are very diverse, but for convenience may be grouped into subfamilies on the basis of sequence similarity. One such family groups together a range of proteins, including ascG, ccpA, cytR, ebgR, fruR, galR, galS, lacI, malI, opnR, purF, rafR, rbtR and scrR [(PUBMED:1639817), (PUBMED:1805309)]. Within this family, the HTH motif is situated towards the N terminus.|
|GO process:||regulation of transcription, DNA-dependent (GO:0006355)|
|GO component:||intracellular (GO:0005622)|
|GO function:||sequence-specific DNA binding transcription factor activity (GO:0003700)|
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- Evolution (species in which this domain is found)
- Literature (relevant references for this domain)
Primary literature is listed below; Automatically-derived, secondary literature is also avaliable.
- Nguyen CC, SaierMHJ r
- Phylogenetic, structural and functional analyses of the LacI-GalR family of bacterial transcription factors.
- FEBS Lett. 1995; 377: 98-102
- Display abstract
Phylogenetic tree construction for 25 sequenced members of the LacI-GalR family (LGF) of transcription factors revealed that almost all branches are similar in length, radiating essentially from a single point. This observation suggests that most of these proteins arose by duplication events which occurred at a specific time in evolutionary history, and that further duplication events were rare. Analyses of the multiple alignment of the LGF proteins lead to suggestions regarding structure-function relationships and reveal that the helix-turn-helix DNA-binding motif of LGF proteins is similar in sequence to those of numerous non-homologous DNA-binding proteins.
- Weickert MJ, Adhya S
- A family of bacterial regulators homologous to Gal and Lac repressors.
- J Biol Chem. 1992; 267: 15869-74
- Display abstract
We describe a family of proteins which regulate transcription of inducible genes in bacteria (GalR-LacI family). An alignment of the proteins in the GalR-LacI family is presented in which these proteins show a very high degree of similarity (60%) throughout the entire sequences. The homology is greatest among the amino-terminal DNA binding domains. Since a portion of the operator sequences occupied by these proteins is also conserved, a similar DNA structure may be required for specific recognition of DNA by members of the GalR-LacI family. Highly conserved motifs involved in effector binding and oligomerization are also identified. This compilation suggests a widespread conservation of these regulators among bacteria, and have strong implications for further study of peptide motifs in domain function, as well as pathways of protein evolution.
- Haydon DJ, Guest JR
- A new family of bacterial regulatory proteins.
- FEMS Microbiol Lett. 1991; 63: 291-5
- Display abstract
A new family of bacterial regulatory proteins has been identified by sequence similarity. The family contains the repressor of the Bacillus subtilis gluconate operon (GntR), the regulators for histidine utilization in Pseudomonas putida (HutCPp) and Klebsiella aerogenes (HutCKa), the repressor (FadR) of fatty acid degradation in Escherichia coli, a regulator involved in the conjugal transfer of the broad host range plasmid pIJ101 (KorA), and three proteins of unidentified function in E. coli (GenA, P30 and PhnF). The proteins share amino acid sequence similarities in a 69-residue N-terminal region. A helix-turn-helix motif is predicted in the most highly-conserved segment of each protein suggesting that they are members of a new family of helix-turn-helix DNA-binding proteins.
- Metabolism (metabolic pathways involving proteins which contain this domain)
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% proteins involved KEGG pathway ID Description 48.00 map00473 D-Alanine metabolism 48.00 map00252 Alanine and aspartate metabolism 1.33 map00030 Pentose phosphate pathway 0.67 map00710 Carbon fixation 0.67 map00720 Reductive carboxylate cycle (CO2 fixation) 0.67 map00620 Pyruvate metabolism 0.67 map00300 Lysine biosynthesis
This information is based on mapping of SMART genomic protein database to KEGG orthologous groups. Percentage points are related to the number of proteins with HTH_LACI domain which could be assigned to a KEGG orthologous group, and not all proteins containing HTH_LACI domain. Please note that proteins can be included in multiple pathways, ie. the numbers above will not always add up to 100%.
- Structure (3D structures containing this domain)
3D Structures of HTH_LACI domains in PDB
PDB code Main view Title 1bdh Purine repressor mutant-hypoxanthine-palindromic operator complex 1bdi Purine repressor mutant-hypoxanthine-palindromic operator complex 1cjg Nmr structure of lac repressor hp62-dna complex 1efa Crystal structure of the lac repressor dimer bound to operator and the anti-inducer onpf 1jfs Purine repressor mutant-hypoxanthine-purf operator complex 1jft Purine repressor mutant-hypoxanthine-purf operator complex 1jh9 Purine repressor mutant-hypoxanthine-purf operator complex 1jwl Structure of the dimeric lac repressor/operator o1/onpf complex 1jye Structure of a dimeric lac repressor with c-terminal deletion and k84l substitution 1jyf Structure of the dimeric lac repressor with an 11-residue c- terminal deletion. 1l1m Solution structure of a dimer of lac repressor dna-binding domain complexed to its natural operator o1 1lbg Lactose operon repressor bound to 21-base pair symmetric operator dna, alpha carbons only 1lbh Intact lactose operon repressor with gratuitous inducer iptg 1lbi Lac repressor 1lcc Structure of the complex of lac repressor headpiece and an base-pair half-operator determined by nuclear magnetic resonance spectroscopy and restrained molecular dynamics 1lcd Structure of the complex of lac repressor headpiece and an base-pair half-operator determined by nuclear magnetic resonance spectroscopy and restrained molecular dynamics 1lqc Lac repressor headpiece (residues 1-56), nmr, 32 structures 1osl Solution structure of a dimeric lactose dna-binding domain complexed to a nonspecific dna sequence 1pnr Purine repressor-hypoxanthine-purf-operator complex 1pru Purine repressor dna-binding domain dna binding 1prv Purine repressor dna-binding domain dna binding 1qp0 Purine repressor-hypoxanthine-palindromic operator complex 1qp4 Purine repressor-hypoxanthine-palindromic operator complex 1qp7 Purine repressor mutant-hypoxanthine-palindromic operator complex 1qpz Purine repressor-hypoxanthine-palindromic operator complex 1qqa Purine repressor mutant-hypoxanthine-palindromic operator complex 1qqb Purine repressor mutant-hypoxanthine-palindromic operator complex 1rzr Crystal structure of transcriptional regulator- phosphoprotein-dna complex 1uxc Fructose repressor dna-binding domain, nmr, minimized structure 1uxd Fructose repressor dna-binding domain, nmr, 34 structures 1vpw Structure of the purr mutant, l54m, bound to hypoxanthine and purf operator dna 1wet Structure of the purr-guanine-purf operator complex 1zay Purine repressor-hypoxanthine-modified-purf-operator complex 1zvv Crystal structure of a ccpa-crh-dna complex 2bjc Nmr structure of a protein-dna complex of an altered specificity mutant of the lac repressor headpiece that mimics the gal repressor 2hsg Structure of transcription regulator ccpa in its dna-free state 2iks Crystal structure of n-terminal truncated dna-binding transcriptional dual regulator from escherichia coli k12 2jcg Apo form of the catabolite control protein a (ccpa) from bacillus megaterium, with the dna binding domain 2kei Refined solution structure of a dimer of lac repressor dna- binding domain complexed to its natural operator o1 2kej Solution structure of a dimer of lac repressor dna-binding domain complexed to its natural operator o2 2kek Solution structure of a dimer of lac repressor dna-binding domain complexed to its natural operator o3 2o20 Crystal structure of transcription regulator ccpa of lactococcus lactis 2pe5 Crystal structure of the lac repressor bound to onpg in repressed state 2pua Crystal structure of the laci family member, purr, bound to dna: minor groove binding by alpha helices 2pub Crystal structure of the laci family member, purr, bound to dna: minor groove binding by alpha helices 2puc Crystal structure of the laci family member, purr, bound to dna: minor groove binding by alpha helices 2pud 2pue 2puf 2pug 3bil Crystal structure of a probable laci family transcriptional regulator from corynebacterium glutamicum 3ctp Crystal structure of periplasmic binding protein/laci transcriptional regulator from alkaliphilus metalliredigens qymf complexed with d-xylulofuranose 3dbi Crystal structure of sugar-binding transcriptional regulator (laci family) from escherichia coli complexed with phosphate 3e3m Crystal structure of a laci family transcriptional regulator from silicibacter pomeroyi 3edc Crystal structure of a 1.6-hexanediol bound tetrameric form of escherichia coli lac-repressor refined to 2.1 resolution 3h5o The crystal structure of transcription regulator gntr from chromobacterium violaceum 3h5t Crystal structure of a transcriptional regulator, lacl family protein from corynebacterium glutamicum 3jvd Crystal structure of putative transcription regulation repressor (laci family) from corynebacterium glutamicum 3kjx Crystal structure of a transcriptional regulator, lacl family protein from silicibacter pomeroyi
- Links (links to other resources describing this domain)
PFAM lacI INTERPRO IPR000843 PROSITE HTH_LACI_FAMILY