In molecular biology, the GntR-like bacterial transcription factors are a family

Protein family

A protein family is a group of evolutionarily-related proteins, and is often nearly synonymous with gene family. The term protein family should not be confused with family as it is used in taxonomy....

 of transcription factors.

Many bacterial

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 transcription regulation

Transcriptional regulation

Transcriptional regulation is the change in gene expression levels by altering transcription rates. -Regulation of transcription:Regulation of transcription controls when transcription occurs and how much RNA is created...

 protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

s bind DNA

DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 through a helix-turn-helix

Helix-turn-helix

In proteins, the helix-turn-helix is a major structural motif capable of binding DNA. It is composed of two α helices joined by a short strand of amino acids and is found in many proteins that regulate gene expression...

 (HTH) motif, which can be classified into subfamilies on the basis of sequence

Sequence (biology)

A sequence in biology is the one-dimensional ordering of monomers, covalently linked within in a biopolymer; it is also referred to as the primary structure of the biological macromolecule.-See also:* Protein sequence* DNA sequence...

 similarities. The HTH GntR family has many members distributed among diverse bacterial groups that regulate various biological processes. It was named GntR after the Bacillus subtilis

Bacillus subtilis

Bacillus subtilis, known also as the hay bacillus or grass bacillus, is a Gram-positive, catalase-positive bacterium commonly found in soil. A member of the genus Bacillus, B. subtilis is rod-shaped, and has the ability to form a tough, protective endospore, allowing the organism to tolerate...

repressor

Repressor

In molecular genetics, a repressor is a DNA-binding protein that regulates the expression of one or more genes by binding to the operator and blocking the attachment of RNA polymerase to the promoter, thus preventing transcription of the genes. This blocking of expression is called...

 of the gluconate operon

Operon

In genetics, an operon is a functioning unit of genomic DNA containing a cluster of genes under the control of a single regulatory signal or promoter. The genes are transcribed together into an mRNA strand and either translated together in the cytoplasm, or undergo trans-splicing to create...

. Family members include GntR, HutC, KorA, NtaR, FadR

Fatty acid metabolism regulator protein FadR

In molecular biology, the fatty acid metabolism regulator protein FadR, is a bacterial transcription factor.Bacteria regulate membrane fluidity by manipulating the relative levels of saturated and unsaturated fatty acids within the phospholipids of their membrane bilayers...

, ExuR, FarR, DgoR and PhnF. The crystal structure

Crystal structure

In mineralogy and crystallography, crystal structure is a unique arrangement of atoms or molecules in a crystalline liquid or solid. A crystal structure is composed of a pattern, a set of atoms arranged in a particular way, and a lattice exhibiting long-range order and symmetry...

 of the FadR protein has been determined. In general, these proteins

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 contain a DNA-binding HTH domain

Protein domain

A protein domain is a part of protein sequence and structure that can evolve, function, and exist independently of the rest of the protein chain. Each domain forms a compact three-dimensional structure and often can be independently stable and folded. Many proteins consist of several structural...

 at the N-terminus, and an effector

Effector

Effector may refer to:*An actuator, in robotics*Effector , a music album by the Experimental Techno group Download*Effector cell, a type of lymphocyte in immunology...

-binding or oligomerisation domain at the C-terminus. The DNA-binding domain is well conserved in structure

Secondary structure

In biochemistry and structural biology, secondary structure is the general three-dimensional form of local segments of biopolymers such as proteins and nucleic acids...

 for the whole of the GntR family, consisting of a 3-helical bundle core with a small beta-sheet (wing); the GntR winged helix

Winged-helix transcription factors

Consisting of about 110 amino acids, the domain in winged-helix transcription factors has four helices and a two-strand beta-sheet.These proteins are classified into 17 families called FoxA-FoxQ....

 structure is similar to that found in several other transcriptional

Transcription (genetics)

Transcription is the process of creating a complementary RNA copy of a sequence of DNA. Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language that can be converted back and forth from DNA to RNA by the action of the correct enzymes...

regulator families. The regions outside the DNA-binding domain are more variable and are consequently used to define GntR subfamilies.