Organization and expression of genes involved in the production of the K88ab antigen.

AUTOR(ES)

Mooi, F R

RESUMO

Escherichia coli K-12 minicells were used to study the expression of the genes located on plasmid pFM205, which contains the genetic determinant of the K88ab antigen. Plasmid pFM205 is composed of a 4,3-megadalton large deoxyribonucleic acid fragment derived from the wild-type K88ab plasmid pRI8801 (51 megadaltons) and the cloning vehicle pBR322. The K88ab deoxyribonucleic acid of pFM205 appeared to express six polypeptides with apparent molecular masses of 81, 30, 29, 27, 26, and 17 kilodaltons, respectively. These polypeptides account for approximately 85% of the coding capacity of the cloned deoxyribonucleic acid. The 26-kilodalton polypeptide was found to react with specific anti-K88ab antibodies and therefore represents the K88ab subunit. The K88ab subunit and at least two other polypeptides (81 and 17 kilodaltons) were translated into precursors which were about 2 kilodaltons larger than the mature proteins. Plasmid pFM205 was used to construct deletion mutants. By analyzing these mutants in minicells the genes of the six polypeptides could be located on the physical map of pFM205. It appeared that deletion of the gene of the 81-kilodalton polypeptide resulted in an altered conformation of the K88ab antigen.

Documentos Relacionados

• Cloning, mapping and expression of the genetic determinant that encodes for the K88ab antigen.
• Construction and characterization of mutants impaired in the biosynthesis of the K88ab antigen.
• K88ab gene of Escherichia coli encodes a fimbria-like protein distinct from the K88ab fimbrial adhesin.
• Demonstration of K88ac and K88ab antigens of Escherichia coli by means of immunoelectrophoresis and immunodiffusion.
• Identification and characterization of precursors in the biosynthesis of the K88ab fimbria of Escherichia coli.