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47  structures 3881  species 2  interactions 4117  sequences 11  architectures

Family: Barstar (PF01337)

Summary: Barstar (barnase inhibitor)

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This is the Wikipedia entry entitled "Barstar". More...

Barstar Edit Wikipedia article

Barstar (barnase inhibitor)
The tightly bound complex between barstar and barnase, the ribonuclease barstar inhibits. Barstar is colored by secondary structure and barnase is colored in blue.[1]
Symbol Barstar
Pfam PF01337
InterPro IPR000468
SCOP 1brs

Barstar is a small protein synthesized by the bacterium Bacillus amyloliquefaciens. Its function is to inhibit the ribonuclease activity of its binding partner barnase, with which it forms an extraordinarily tightly bound complex within the cell until barnase is secreted.[2][3] Expression of barstar is necessary to counter the lethal effect of expressed active barnase. The structure of the barnase-barstar complex is known.[4]


  1. ^ PDB 1BRS; Buckle AM, Schreiber G, Fersht AR (August 1994). "Protein-protein recognition: crystal structural analysis of a barnase-barstar complex at 2.0-A resolution". Biochemistry 33 (30): 8878–89. doi:10.1021/bi00196a004. PMID 8043575. 
  2. ^ Hartley RW (1989). "Barnase and barstar: two small proteins to fold and fit together". Trends Biochem. Sci. 14 (11): 450–454. doi:10.1016/0968-0004(89)90104-7. PMID 2696173. 
  3. ^ Hartley RW (1988). "Barnase and barstar. Expression of its cloned inhibitor permits expression of a cloned ribonuclease". J. Mol. Biol. 202 (4): 913–915. doi:10.1016/0022-2836(88)90568-2. PMID 3050134. 
  4. ^ Fersht AR, Buckle AM, Schreiber G (1994). "Protein-protein recognition: crystal structural analysis of a barnase-barstar complex at 2.0-A resolution". Biochemistry 33 (30): 8878–8889. doi:10.1021/bi00196a004. PMID 8043575. 

This article incorporates text from the public domain Pfam and InterPro IPR000468

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

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Literature references

  1. Buckle AM, Schreiber G, Fersht AR; , Biochemistry 1994;33:8878-8889.: Protein-protein recognition: crystal structural analysis of a barnase-barstar complex at 2.0-A resolution. PUBMED:8043575 EPMC:8043575

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External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR000468

Barstar is a small single chain protein. Barnase is the extracellular ribonuclease INTERPRO of Bacillus amyloliquefaciens, and barstar its specific intracellular inhibitor [PUBMED:2696173, PUBMED:3050134]. Expression of barstar is necessary to counter the lethal effect of expressed active barnase. The structure of the barnase-barstar complex is known [PUBMED:8043575].

Domain organisation

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Curation and family details

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Seed source: Sarah Teichmann
Previous IDs: none
Type: Domain
Author: Finn RD, Bateman A
Number in seed: 106
Number in full: 4117
Average length of the domain: 80.30 aa
Average identity of full alignment: 38 %
Average coverage of the sequence by the domain: 74.05 %

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HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 80369284 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 21.0 21.0
Trusted cut-off 21.0 21.0
Noise cut-off 20.9 20.9
Model length: 79
Family (HMM) version: 14
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Species distribution

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Archea Archea Eukaryota Eukaryota
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Viroids Viroids Unclassified sequence Unclassified sequence


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There are 2 interactions for this family. More...

Barstar Ribonuclease


For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Barstar domain has been found. There are 47 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

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