1887

Abstract

SUMMARY: Cell-envelope fractions were isolated from the rapidly growing saprophyte following growth in glycerol/asparagine medium under both iron-limited (0·02 μg Fe ml) and iron-sufficient (2·0 to 4·0 μg Fe ml) conditions. Examination of these preparations by SDS-PAGE demonstrated the production of at least four additional proteins when iron was limiting. These iron-regulated envelope proteins (IREPs) were ascribed apparent molecular masses of 180 kDa (protein I), 84 kDa (protein II), 29 kDa (protein III) and 25 kDa (protein IV). All four proteins were present in both cell-wall and membrane preparations but spheroplast preparations were devoid of the 29 kDa protein. Attempts at labelling the proteins with FeCl or Fe-exochelin, the siderophore for iron uptake, were unsuccessful, though this was attributed to the denatured state of the proteins following electrophoresis. Antibodies were raised to each of the four proteins; the one raised to protein III inhibited exochelin-mediated iron uptake into iron-deficiently grown cells by 70% but was ineffective against iron uptake into iron-sufficiently grown cells. As exochelin is taken up into both types of cells by a similar process, protein III may not be a simple receptor for iron uptake though the results imply some function connected with this process. The role of the other IREPs is less certain.

Loading

Article metrics loading...

/content/journal/micro/10.1099/00221287-133-8-2107
1987-08-01
2019-08-19
Loading full text...

Full text loading...

http://instance.metastore.ingenta.com/content/journal/micro/10.1099/00221287-133-8-2107
Loading
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error