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Title: Binding of ATP by pertussis toxin and isolated toxin subunits

The binding of ATP to pertussis toxin and its components, the A subunit and B oligomer, was investigated. Whereas, radiolabeled ATP bound to the B oligomer and pertussis toxin, no binding to the A subunit was observed. The binding of ({sup 3}H)ATP to pertussis toxin and the B oligomer was inhibited by nucleotides. The relative effectiveness of the nucleotides was shown to be ATP > GTP > CTP > TTP for pertussis toxin and ATP > GTP > TTP > CTP for the B oligomer. Phosphate ions inhibited the binding of ({sup 3}H)ATP to pertussis toxin in a competitive manner; however, the presence of phosphate ions was essential for binding of ATP to the B oligomer. The toxin substrate, NAD, did not affect the binding of ({sup 3}H)ATP to pertussis toxin, although the glycoprotein fetuin significantly decreased binding. These results suggest that the binding site for ATP is located on the B oligomer and is distinct from the enzymatically active site but may be located near the eukaryotic receptor binding site.
Authors:
; ;  [1]
  1. (Center for Biologics Evaluation and Research, Bethesda, MD (USA))
Publication Date:
OSTI Identifier:
6253957
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemistry; (USA); Journal Volume: 29:26
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; ATP; CROSS-LINKING; TOXINS; BACTERIA; BIOCHEMICAL REACTION KINETICS; IONS; NUCLEOTIDES; PHOSPHATES; TRITIUM COMPOUNDS; ANTIGENS; CHARGED PARTICLES; CHEMICAL REACTIONS; HYDROGEN COMPOUNDS; KINETICS; MATERIALS; MICROORGANISMS; ORGANIC COMPOUNDS; OXYGEN COMPOUNDS; PHOSPHORUS COMPOUNDS; POLYMERIZATION; REACTION KINETICS; TOXIC MATERIALS 550201* -- Biochemistry-- Tracer Techniques