What does a helix-turn-helix DNA binding protein contain?

What does a helix-turn-helix DNA binding protein contain?

In proteins, the helix-turn-helix (HTH) is a major structural motif capable of binding DNA. Each monomer incorporates two α helices, joined by a short strand of amino acids, that bind to the major groove of DNA. The HTH motif occurs in many proteins that regulate gene expression.

What is the structure of a helix loop helix protein?

Structure. The motif is characterized by two α-helices connected by a loop. In general, transcription factors (including this type) are dimeric, each with one helix containing basic amino acid residues that facilitate DNA binding.

Is Helix-turn-Helix a domain?

Abstract. The helix-turn-helix (HTH) domain is a common denominator in basal and specific transcription factors from the three super-kingdoms of life. At its core, the domain comprises of an open tri-helical bundle, which typically binds DNA with the 3rd helix.

Where are helix-turn-helix proteins found?

The helix-turn-helix (HTH) motif is commonly found in proteins that bind DNA, especially transcription factors. In recognizing DNA, the last helix of the HTH motif that is commonly referred to as the recognition helix inserts into the DNA major groove to mediate base-specific DNA recognition.

What is homeodomain protein?

The homeodomain is a highly conserved 60‐amino‐acid protein domain that is encoded by the homeobox and is found in organisms as diverse as mammals, insects, plants and yeast. Homeodomains function as DNA binding domains and are found in many transcription factors that control development and cell fate decisions.

Are common DNA binding domains in proteins?

However, only a rather small number of protein families are DNA-binding. For instance, more than 2000 of the ~20,000 human proteins are “DNA-binding”, including about 750 Zinc-finger proteins….DNA-binding protein in genomes.

Species DNA-binding proteins DNA-binding families
Drosophila melanogaster (fruit fly) 2620 283

What is the function of helix loop helix?

The basic helix-loop-helix (bHLH) proteins form a large superfamily of transcriptional regulators that are found in organisms from yeast to humans and function in critical developmental processes, including sex determination and the development of the nervous system and muscles.

Is an example of a helix-turn-helix motif?

The helix-turn-helix motif is a common tertiary structure motif found in DNA-binding proteins. Examples in Proteopedia include the Lac repressor and Biotin Protein Ligase.

What do DNA binding motifs do?

The DNA binding proteins have a specific folding pattern which is made of repeated nucleotide sequences called as DNA binding motifs. These motifs permit the binding of DNA binding proteins such as transcription factors to the target sequence. It is composed of recognition region and stabilization region.

What has a DNA binding domain?

Many proteins involved in the regulation of gene expression contain DNA-binding domains. For example, proteins that regulate transcription by binding DNA are called transcription factors. For example, the DNA-cutting enzyme DNAse I cuts DNA almost randomly and so must bind to DNA in a non-sequence-specific manner.