Domain-specific bias in arginine/lysine usage by protein toxins.
The content of lysine and arginine residues in a number of A-B type protein toxins has been examined. It is found that the A subunit, or its equivalent, often shows a strong bias in the type of basic amino acid residue used tending towards nearly exclusive use of either arginine or lysine rather than use of both, whereas the B subunit or its equivalent shows no such bias. Although arginine codons are GC-rich and lysine codons are AT-rich, the content of GC and AT in the genes coding for the toxins does not adequately explain this bias. Other explanations are discussed, including the possibility that the bias is linked to catalytic function or membrane interaction. Understanding this bias may yield valuable insights into toxin structure and function. Furthermore, identification of bias in sequences may be a useful tool for identifying new toxins and their domains.
London
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Department of Biochemistry, State University of New York, Stony Brook 11794-5215.
Luongo
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D036002:ADP Ribose Transferases; D001120:Arginine / Q000032:analysis*; D001427:Bacterial Toxins / Q000032:analysis; D001482:Base Composition; D002772:Cholera Toxin / Q000032:analysis; D003062:Codon; D004167:Diphtheria Toxin / Q000032:analysis; D004768:Enterotoxins / Q000032:analysis; D029968:Escherichia coli Proteins; D005098:Exotoxins / Q000032:analysis; D008239:Lysine / Q000032:analysis*; D012276:Ricin / Q000032:analysis; D022603:Shiga Toxins; D014118:Toxins, Biological / Q000032:analysis* / Q000235:genetics; D037521:Virulence Factors; D010566:Virulence Factors, Bordetella / Q000032:analysis; D000097668:Pseudomonas aeruginosa Exotoxin A
D036002:ADP Ribose Transferases; D001120:Arginine; D001427:Bacterial Toxins; D002772:Cholera Toxin; D003062:Codon; D004167:Diphtheria Toxin; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D005098:Exotoxins; D008239:Lysine; D012276:Ricin; D022603:Shiga Toxins; D014118:Toxins, Biological; D037521:Virulence Factors; D010566:Virulence Factors, Bordetella; D000097668:Pseudomonas aeruginosa Exotoxin A; C027538:heat-labile enterotoxin, E coli