Open AccessStreptococcus pneumoniae type 3 encodes a protein highly similar to the human glutamate decarboxylase (GAD 65 )
Author(s) -
García Ernesto,
López Rubens
Publication year - 1995
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1995.tb07870.x
Subject(s) - epitope , biology , gene , microbiology and biotechnology , open reading frame , streptococcus pneumoniae , serotype , southern blot , nucleic acid sequence , antibody , sequence analysis , peptide sequence , biochemistry , genetics , antibiotics
A 2.5‐kb Sca I fragment of the type 3 pneumococcal strain 406 DNA containing a 1425‐nucleotide open reading frame ( gadA ) and encoding a 475‐amino acid protein ( M rmr 54427) was characterised. The gene gadA was expressed in Salmonella typhimurium . Pulsed‐field gel electrophoresis and Southern blotting analysis of DNAs prepared from several pneumococcal serotypes showed that only those clinical isolates belonging to serotype 3 harbour the gadA gene. Sequence comparison of GadA with proteins included in the data banks revealed the highest similarity with human glutamate decarboxylase (GAD 65 ) (59% similarity, 28% identity). Auto‐antibodies to GAD 65 have been associated with the onset of insulin‐dependent diabetes mellitus. Interestingly, several epitopes of GAD 65 that have been identified as immunodominant are particularly well conserved in the pneumococcal GadA.