Barnase

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Structures	Swiss-model
Domains	InterPro

Barnase
Barnase
	The tightly bound complex between barnase and its inhibitor barstar. Barnase is colored by secondary structure and barstar is colored in blue.
Identifiers
Symbol	Barnase
PDB	1BRS More structures
UniProt	P00648
Other data
EC number	3.1.27.-
Structures
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Structures	Swiss-model
Domains	InterPro

Barnase (a portmanteau of "BActerial" "RiboNucleASE") is a bacterial protein that consists of 110 amino acids and has ribonuclease activity. It is synthesized and secreted by the bacterium Bacillus amyloliquefaciens, but is lethal to the cell when expressed without its inhibitor barstar. The inhibitor binds to and occludes the ribonuclease active site, preventing barnase from damaging the cell's RNA after it has been synthesized but before it has been secreted. The barnase/barstar complex is noted for its extraordinarily tight protein-protein binding, with an on-rate of 10⁸s⁻¹M⁻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): 8878–8889. doi:10.1021/bi00196a004. PMID 8043575.

[pmid8043575-1] 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): 8878–8889. doi:10.1021/bi00196a004. PMID 8043575.

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