A Conserved Acidic Amino Acid Mediates the Interaction between Modulators and Co-Chaperones in Enterobacteria

Chintakayala, Kiran; Grainger, David C.

doi:10.1016/j.jmb.2011.05.043

Cited by 6 publications

(9 citation statements)

References 14 publications

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“…In combination with the structural studies described above molecular genetics has been used to reveal precise CbpA interaction surfaces ( 7 , 12 ). A basic patch on the surface of the J-domain, comprising amino acids R26, R30 and H33, interacts with CbpM side chains E64, T75 and E62 ( 11 , 12 ). Strikingly, this is the same surface of CbpA that contacts DnaK ( 11 ).…”

Section: Introductionmentioning

confidence: 99%

DNA recognition by Escherichia coli CbpA protein requires a conserved arginine–minor-groove interaction

Chintakayala

Sellars

Singh

et al. 2015

Nucleic Acids Research

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Curved DNA binding protein A (CbpA) is a co-chaperone and nucleoid associated DNA binding protein conserved in most γ-proteobacteria. Best studied in Escherichia coli, CbpA accumulates to >2500 copies per cell during periods of starvation and forms aggregates with DNA. However, the molecular basis for DNA binding is unknown; CbpA lacks motifs found in other bacterial DNA binding proteins. Here, we have used a combination of genetics and biochemistry to elucidate the mechanism of DNA recognition by CbpA. We show that CbpA interacts with the DNA minor groove. This interaction requires a highly conserved arginine side chain. Substitution of this residue, R116, with alanine, specifically disrupts DNA binding by CbpA, and its homologues from other bacteria, whilst not affecting other CbpA activities. The intracellular distribution of CbpA alters dramatically when DNA binding is negated. Hence, we provide a direct link between DNA binding and the behaviour of CbpA in cells.

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Section: Introductionmentioning

confidence: 99%

DNA recognition by Escherichia coli CbpA protein requires a conserved arginine–minor-groove interaction

Chintakayala

Sellars

Singh

et al. 2015

Nucleic Acids Research

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“…The only highly conserved CbpM polar residue facing CbpA is Glu62. This residue forms a hydrogen bond with His33 CbpA of the conserved H-P-D sequence motif and was recently shown to be essential for CbpA binding [18]. In addition to Glu62, the CbpM interface involves four other acidic residues (Glu22, Glu64, Asp66 and Glu79) while CbpA Jdom contributes seven basic residues (Lys19, Lys22, Arg26, Arg27, Arg30, His33 and Lys38) (Fig.…”

Section: Resultsmentioning

confidence: 97%

“…Binding of CbpA to intrinsically curved DNA [13], which is frequently found in promoter regions [40], may be relevant to its involvement in transcription regulation [18]. In Streptomyces coelicolor DnaK acts as a transcriptional co-repressor, forming stable ternary complexes with HspR and DNA [41].…”

Section: Discussionmentioning

confidence: 99%

Structure of CbpA J-Domain Bound to the Regulatory Protein CbpM Explains Its Specificity and Suggests Evolutionary Link between CbpM and Transcriptional Regulators

et al. 2014

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CbpA is one of the six E. coli DnaJ/Hsp40 homologues of DnaK co-chaperones and the only one that is additionally regulated by a small protein CbpM, conserved in γ-proteobacteria. CbpM inhibits the co-chaperone and DNA binding activities of CbpA. This regulatory function of CbpM is accomplished through reversible interaction with the N-terminal J-domain of CbpA, which is essential for the interaction with DnaK. CbpM is highly specific for CbpA and does not bind DnaJ despite the high degree of structural and functional similarity between the J-domains of CbpA and DnaJ. Here we report the crystal structure of the complex of CbpM with the J-domain of CbpA. CbpM forms dimers and the J-domain of CbpA interacts with both CbpM subunits. The CbpM-binding surface of CbpA is highly overlapping with the CbpA interface for DnaK, providing a competitive model for regulation through forming mutually exclusive complexes. The structure also provides the explanation for the strict specificity of CbpM for CbpA, which we confirmed by making mutants of DnaJ that became regulated by CbpM. Interestingly, the structure of CbpM reveals a striking similarity to members of the MerR family of transcriptional regulators, suggesting an evolutionary connection between the functionally distinct bacterial co-chaperone regulator CbpM and the transcription regulator HspR.

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“…They are members of the heat shock protein (Hsp) family, which have been shown to play important roles in the response to numerous stress conditions including osmotic stress and also can act as co-chaperones by stimulating the activity of other chaperones such as DnaK [63-65]. TM2 domain proteins are composed of a pair of alpha helices connected by a short linker.…”

Section: Discussionmentioning

confidence: 99%

Functional Environmental Screening of a Metagenomic Library Identifies stlA; A Unique Salt Tolerance Locus from the Human Gut Microbiome

et al. 2013

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Functional environmental screening of metagenomic libraries is a powerful means to identify and assign function to novel genes and their encoded proteins without any prior sequence knowledge. In the current study we describe the identification and subsequent analysis of a salt-tolerant clone from a human gut metagenomic library. Following transposon mutagenesis we identified an unknown gene (stlA, for “salt tolerance locus A”) with no current known homologues in the databases. Subsequent cloning and expression in Escherichia coli MKH13 revealed that stlA confers a salt tolerance phenotype in its surrogate host. Furthermore, a detailed in silico analysis was also conducted to gain additional information on the properties of the encoded StlA protein. The stlA gene is rare when searched against human metagenome datasets such as MetaHit and the Human Microbiome Project and represents a novel and unique salt tolerance determinant which appears to be found exclusively in the human gut environment.

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A Conserved Acidic Amino Acid Mediates the Interaction between Modulators and Co-Chaperones in Enterobacteria

Cited by 6 publications

References 14 publications

DNA recognition by Escherichia coli CbpA protein requires a conserved arginine–minor-groove interaction

DNA recognition by Escherichia coli CbpA protein requires a conserved arginine–minor-groove interaction

Structure of CbpA J-Domain Bound to the Regulatory Protein CbpM Explains Its Specificity and Suggests Evolutionary Link between CbpM and Transcriptional Regulators

Functional Environmental Screening of a Metagenomic Library Identifies stlA; A Unique Salt Tolerance Locus from the Human Gut Microbiome

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