title: Complementation of peptides of barnase, extracellular ribonuclease of Bacillus amyloliquefaciens.
abstract: Recovery of ribonuclease activity by complementation of peptides of barnase is reported. Activity is restored to barnase-(1-102), which lacks eight amino acids from its COOH terminus, by combination with peptides-(88-110), -(95-110), or -(99-108), and also with succinylated peptide-(88-110). The dissociation constants are about 8 X 10(-6) M for the first two combinations and little, if any, greater for the other two. Based on barnase-(1-102) concentration, up to 80% of native activity is obtained with peptide-(88-110) but only 5 to 20% with the others. The octapeptide-(103-110), equivalent to the residues missing from barnase-(1-102), does not complement barnase-(1-102), suggesting that an intact sequence about His-102 and Tyr-103 is required for activity. Barstar, the natural inhibitor of barnase, completely inhibits all activity of the complementing peptides.
mesh_terms: D000595:Amino Acid Sequence; D001407:Bacillus / Q000201:enzymology*; D001426:Bacterial Proteins / Q000494:pharmacology; D010455:Peptides; D012260:Ribonucleases / Q000037:antagonists & inhibitors / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D001426:Bacterial Proteins; D010455:Peptides; D012260:Ribonucleases; C019760:Bacillus amyloliquefaciens ribonuclease