Format

Send to

Choose Destination
Nucleic Acids Res. 1984 May 25;12(10):4063-9.

The amino-acid sequence of two non-toxic mutants of diphtheria toxin: CRM45 and CRM197.

Abstract

The amino-acid sequences of two diphtheria toxin-related, non-toxic proteins, CRM45 and CRM197 , were deduced from the complete sequence of their genes: tox 45 and tox 197. CRM45 lacks the last 149 C-terminal amino-acid residues, but is otherwise identical to diphtheria toxin: a single C----T transition introduces an "ochre" (TAA) termination signal in tox 45, after the codon for threonine-386. A single G----A transition was also found in tox 197, leading to the substitution of glycine-52, present in the wild-type toxin, with glutamic acid in CRM197 . This aminoacid change is responsible for the loss of the NAD:EF2 ADP-ribosyltransferase activity in CRM197 , due most probably to an alteration of the NAD+ binding site.

PMID:
6427753
PMCID:
PMC318816
DOI:
10.1093/nar/12.10.4063
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Silverchair Information Systems Icon for PubMed Central
Loading ...
Support Center