General Information

Database accession: MF2120019

Name: Escherichia coli met repressor (MetJ)

PDB ID: 1cmb PDB

Experimental method: X-ray (1.80 Å)

Assembly: homodimer

Source organism: Escherichia coli

Primer publication of the structure:

Rafferty JB, Somers WS, Saint-Girons I, Phillips SE
Three-dimensional crystal structures of Escherichia coli met repressor with and without corepressor.

(1989) Nature 341: 705-10

PMID: 2677753 PubMed

Abstract:

The three-dimensional crystal structure of met repressor, in the presence or absence of bound corepressor (S-adenosylmethionine), shows a dimer of intertwined monomers, which do not have the helix-turn-helix motif characteristic of other bacterial repressor and activator structures. We propose that the interaction of met repressor with DNA occurs through either a pair of symmetry-related alpha-helices or a pair of beta-strands, and suggest a model for binding of several dimers to met operator regions.


Function and Biology Annotations from the GeneOntology database. Only terms that fit at least two of the interacting proteins are shown.

Molecular function:

transcription factor activity, sequence-specific DNA binding Interacting selectively and non-covalently with a specific DNA sequence in order to modulate transcription. The transcription factor may or may not also interact selectively with a protein or macromolecular complex. GeneOntology

DNA binding Any molecular function by which a gene product interacts selectively and non-covalently with DNA (deoxyribonucleic acid). GeneOntology

Biological process:

methionine biosynthetic process The chemical reactions and pathways resulting in the formation of methionine (2-amino-4-(methylthio)butanoic acid), a sulfur-containing, essential amino acid found in peptide linkage in proteins. GeneOntology

transcription, DNA-templated The cellular synthesis of RNA on a template of DNA. GeneOntology

negative regulation of transcription, DNA-templated Any process that stops, prevents, or reduces the frequency, rate or extent of cellular DNA-templated transcription. GeneOntology

Cellular component:

cytosol The part of the cytoplasm that does not contain organelles but which does contain other particulate matter, such as protein complexes. GeneOntology

Structure Summary Structural annotations of the participating protein chains.

Entry contents: 2 distinct polypeptide molecules

Chains: A, B

Notes: No modifications of the original PDB file. Chain identifiers are identical with the PDB's identifiers.

Number of unique protein segments: 1


Chain A

Name: Met repressor

Source organism: Escherichia coli

Length: 104 residues

Sequence:Sequence according to PDB SEQRESAEWSGEYISPYAEHGKKSEQVKKITVSIPLKVLKILTDERTRRQVNNLRHATNSELLCEAFLHAFTGQPLPDDADLRKERSDEIPEAAKEIMREMGINPETWEY

UniProtKB AC: P0A8U6 (positions: 2-105) UniProt Coverage: 99%

UniRef90 AC: UniRef90_A7ZUF7 (positions: 2-105) UniRef90

Chain B

Name: Met repressor

Source organism: Escherichia coli

Length: 104 residues

Sequence:Sequence according to PDB SEQRESAEWSGEYISPYAEHGKKSEQVKKITVSIPLKVLKILTDERTRRQVNNLRHATNSELLCEAFLHAFTGQPLPDDADLRKERSDEIPEAAKEIMREMGINPETWEY

UniProtKB AC: P0A8U6 (positions: 2-105) UniProt Coverage: 99%

UniRef90 AC: UniRef90_A7ZUF7 (positions: 2-105) UniRef90

Evidence Evidence demonstrating that the participating proteins are unstructured prior to the interaction and their folding is coupled to binding.

Complex evidence:

MetJ was shown by differential scanning calorimetry to follow a two-state folding and dimerization (PMID: 1390748).

Related Structure(s) Structures from the PDB that contain the same number of proteins, and the proteins from the two structures show a sufficient degree of pairwise similarity, i.e. they belong to the same UniRef90 cluster (the full proteins exhibit at least 90% sequence identity) and convey roughly the same region to their respective interactions (the two regions from the two proteins share a minimum of 70% overlap).

There are 9 related structures in the Protein Data Bank:





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