Involvement of Residues 147VYYEIGK153 in Binding of Lethal Factor to Protective Antigen of Bacillus anthracis

• Published in: Biochemical and biophysical research communications Vol. 280; no. 1; pp. 158 - 163
• Main Authors: Gupta, Pankaj, Singh, Aparna, Chauhan, Vibha, Bhatnagar, Rakesh
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 12.01.2001
• Subjects: Amino Acid Sequence; Amino Acid Substitution; Animals; Antigens, Bacterial; Bacillus anthracis - pathogenicity; Bacterial Toxins - chemistry; Bacterial Toxins - metabolism; Bacterial Toxins - toxicity; Base Sequence; Binding Sites; Binding, Competitive; Carrier Proteins - chemistry; Carrier Proteins - metabolism; Carrier Proteins - toxicity; Cell Line; Cell Survival - drug effects; Cloning, Molecular; DNA Primers; Escherichia coli; Macrophages - drug effects; Molecular Sequence Data; Mutagenesis, Site-Directed; Receptors, Cell Surface - drug effects; Receptors, Cell Surface - physiology; Recombinant Proteins - chemistry; Recombinant Proteins - metabolism; Recombinant Proteins - toxicity; Structure-Activity Relationship
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1006/bbrc.2000.4099

Anthrax toxin is a complex of protective antigen (PA, 735 aa), lethal factor (LF, 776 aa), and edema factor (EF, 767 aa). PA binds to cell surface receptors and is cleaved by cell surface proteases into PA63, while LF and EF compete for binding to PA63. The PA63–LF/EF complex is internalized into the cytosol and causes different pathogenic responses in animals and cultured cells. 1–300 amino acid residues of LF have been viewed as the region responsible for the high affinity binding of LF to PA. Amino acid analysis of LF and EF revealed a common stretch of 7 amino acids (147VYYEIGK153). In the present study, each amino acid of this stretch was replaced by alanine at a time. Y148A, Y149A, I151A, and K153A mutants were found to be deficient in their ability to lyse J774A.1 cells and their binding ability to PA63 was drastically reduced. We propose that these four amino acids play a crucial role in the process of binding of LF to PA63.